Alkene metatheses in transition metal coordination spheres:dimacrocyclizations that join trans positions of square-planarplatinum complexes to give topologically novel diphosphine ligands

Takanori Shima, Eike B. Bauer, Frank Hampel and J. A. Gladysz*Institut für Organische Chemie, Friedrich-Alexander-Universität Erlangen-Nürnberg,Henkestrasse 42, 91054 Erlangen, Germany

Received 6th January 2004, Accepted 11th February 2004First published as an Advance Article on the web 24th February 2004

The alkene-containing phosphines PPh((CH2)nCH��CH2)2)2 (4) are prepared from PPhH2, n-BuLi, and thecorresponding bromoalkenes (1 : 2 : 2), and combined with the platinum tetrahydrothiophene complex[Pt(µ-Cl)(C6F5)(S(CH2CH2–)2)]2 (12) to give the square-planar adducts trans-(Cl)(C6F5)Pt(PPh((CH2)nCH��CH2)2)2

(11, 93–73%; n = a, 2; b, 3; c, 4; d, 5; e, 6; f, 8). Ring-closing metatheses with Grubbs’ catalyst (2) are studied. With

11e, two isomers of trans-(Cl)(C6F5)Pt(PPh(CH2)14P(CH2)14Ph) (15e) are isolated after hydrogenation. Both form via

dimacrocyclization between the trans-phosphine ligands, but differ in the dispositions of the PPh rings (syn, 31%;

anti, 7%). The alternative intraligand metathesis product trans-(Cl)(C6F5)Pt(PPh(CH2)14)2 (16e) is independentlyprepared by (i) protecting 4e as a borane adduct, H3B�PPh((CH2)6CH��CH2)2, (ii) cyclization with 2 and

hydrogenation to give H3B�PPh(CH2)14, (iii) deprotection and reaction with 12. The sample derived from 11e contains≤2% 16e; mass spectra suggest that the other products are dimers or oligomers. The structures of syn-15e, anti-15eand 16e are verified crystallographically, and the macrocycle conformations analyzed. As expected from the (CH2)n

segment length, 11a undergoes intraligand metathesis to give (Z,Z )-trans-(Cl)(C6F5)Pt(PPh(CH2)2CH��CH(CH2)2)2

(86%), as confirmed by a crystal structure of the hydrogenation product. Although 11b does not yield tractable

products, 11c gives syn-(E,E )-trans-(Cl)(C6F5)Pt(PPh(CH2)4CH��CH(CH2)4P(CH2)4CH��CH(CH2)4Ph) (21%). This

structure, and that of the hydrogenation product (syn-15c; 95%), are verified crystallographically. Analogoussequences with 11d,f give syn-15d,f (5 and 14% overall).

IntroductionAlkene metathesis is seeing increasing use in syntheses ofmetal-containing molecules.1 Among many applications, thegeneration of topologically novel metallo- and metallamacro-cycles has attracted particular interest. This rapidly growingtheme has its origins in Sauvage’s elegant syntheses ofcatenanes,2 and has been further developed by ourselves 3,4

and others.5 In our previous full paper,3d we studied the seriesof square-planar sixteen-valence-electron platinum complexestrans-(Cl)(C6F5)Pt(PPh2(CH2)nCH��CH2)2 (1) shown in Scheme1. These feature monophosphine ligands with a polymethylenebridge to a terminal alkenyl group. Ring-closing metatheses

Scheme 1 Monomacrocyclizations involving trans phosphine ligandswith one alkene-containing substituent.

with Grubbs’ catalyst (2) gave high yields of thirteen to twenty-three membered macrocycles featuring unusual trans-spanningdiphosphine ligands.6 Mixtures of E/Z C��C isomers wereobtained, but were easily hydrogenated to the saturated analogs3, which were robust and readily crystallized.

We established the feasibility of analogous reactionsequences with substituted polymethylene bridges 3d and relatedsquare-planar rhodium complexes.3c However, we wonderedwhether this chemistry could be extended to topologically morecomplicated substrates. In particular, what might occur withsimilar complexes of phosphines containing two polymethylenebridges to terminal alkenyl groups – e.g., PPh((CH2)nCH��CH2)2

(4)? As generalized in Scheme 2, two cyclization modes wouldbe possible: (a) reaction between the trans phosphine ligands(interligand metathesis) to give an adduct of a macrocyclicdiphosphine, also a metalladimacrocycle (II), or (b) reactionwithin the phosphine ligands (intraligand metathesis) to give abis(adduct) of a cyclic monophosphine (III).

The feasibility of the second pathway had been explicitlydemonstrated for the rhenium complexes 5h,i shown inScheme 3, which feature one ligand of the type 4 (n = 6). The

Scheme 2 Possible ring-closing metathesis modes for trans donorligands with two alkene-containing substituents.

DO

I:1

0.1

03

9/ b

40

01

56

g

1012 D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8 T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 4

metallomacrocycles 6h,i could be isolated in 94–81% yields.The tungsten complex 7 in Scheme 4, which features threesuch ligands, is also relevant. It gave a complicated and nearlyintractable mixture of all possible cyclization products (8, 9,10), as established by mass spectrometric, HPLC, and crystallo-graphic data. Although no attempt was made to vary thelengths of the (CH2)n segments, it was evident that a simplertype of test substrate was needed. Accordingly, platinumcomplexes of 4, trans-(Cl)(C6F5)Pt(PPh((CH2)nCH��CH2)2)2

(11), were selected for intensive study.In this paper, we describe the partitioning of 11 between the

cyclization modes in Scheme 2 as a function of the numberof methylene groups. Depending upon the chain length,either can dominate. However, dimeric or oligomeric speciesderived from intermolecular metathesis are generally the majorproducts. Nonetheless, significant quantities of topologicallynovel diphosphine complexes of the type II can be accessedfrom several substrates. These would require lengthy synthesesvia conventional methodologies. The crystal structures offour such compounds are determined, and their conformationalfeatures analyzed in detail. A small portion of this work hasbeen communicated.3b

Results

1 Starting phosphines and complexes

As shown in eqn. (1), commercial PPhH2 was successivelytreated at 0 �C with n-BuLi (2.0–2.1 equiv.) and then anα,ω-bromoalkene Br(CH2)nCH��CH2 (n = a, 2; b, 3; c, 4; d, 5;e, 6; f, 8; 2.0–2.1 equiv.). Workups gave the requisite tertiaryphosphines 4a–f as colorless oils in 98–89% yields. The bromo-alkenes were either commercially available or prepared fromthe corresponding alcohols as reported earlier.3d Other syn-theses of 4a,b have been published,7,8 and the preparation of 4eby this procedure has been described previously.3c

Scheme 3 Monomacrocyclizations involving phosphine ligands withtwo alkene-containing substituents.

(1)

The phosphines 4a–f were combined with the platinum tetra-hydrothiophene complex [Pt(µ-Cl)(C6F5)(S(CH2CH2–)2)]2 (12) 9

under conditions used to prepare the educts 1 in Scheme 1 earl-ier.10 As shown in Scheme 5, workups gave the bis(phosphine)complexes 11a–f as colorless oils in 93–73% yields. The newphosphines and platinum complexes were characterized byNMR (1H, 13C, 31P) and IR spectroscopy, mass spectrometry,and microanalyses, as summarized in the experimental section.The spectroscopic properties of 11a–f were similar to those ofthe educts in Scheme 1 and related triarylphosphine complexesreported previously.11

2 Ring-closing metathesis of 11e

Alkene metatheses were conducted under conditions similar tothose used in Scheme 1. As shown in Scheme 6, 11e (ca. 0.0034M) and 2 (10 mol%, added in two portions) were reacted inrefluxing CH2Cl2. Although the catalyst loading might appearsomewhat high, it should be divided by two to normalize tothe number of ring closures. The mixture was filtered throughalumina to separate the catalyst residue. The metathesisproducts, for which 13e and 14e are the only possiblemonomeric structures, were obtained in 97% yield. The samplewas characterized as described for 11a–f.

The 1H NMR spectrum showed no terminal alkene residues,indicating metathesis to be ≥98% complete. Accordingly, newCH��CH signals were detected between 5.20 and 5.35 ppm,presumably due to both E and Z isomers. The 31P NMRspectrum exhibited a multitude of peaks, the dominant oneof which represented 44% of the total area. The 13C NMRspectrum exhibited an even more complex mixture of peaks.These were not tabulated, but only signals in the aromatic/alkene (132–126.5 ppm) and aliphatic (32.8–23.0 ppm) regionswere observed.

The microanalysis fit the formulae of 13e, 14e, or relatedspecies derived from intermolecular metathesis. The massspectrum showed a significant ion with a mass correspondingto [13e � Cl]� or [14e � Cl]� (m/z 966, 45% relative intensity).Another ion had the formal composition [2�13e � Cl]� or[2�14e � Cl]� (m/z 1969, 30%), indicating the presence ofdimeric or oligomeric byproducts. Analogous ions werenot observed for the macrocyclizations in Scheme 1. In orderto simplify further analysis and product isolation, a hydrogen-ation was conducted.

The metathesis mixture was treated with H2 (1 atm) in thepresence of 10% Pd/C (Scheme 6). Filtration through alumina

Scheme 5 Synthesis of substrates for alkene metatheses.

Scheme 4 Polymacrocyclizations involving phosphine ligands with two alkene-containing substituents.

1013D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

Scheme 6 Ring-closing metathesis/hydrogenation sequence for 11e.

gave the crude saturated macrocycles (77%), for which 15e and16e are the only possible monomeric structures. The 1H NMRspectrum showed that all double bonds had been reduced,but the 31P NMR spectrum still exhibited many signals. Thedominant peak represented 52% of the total area, and matchedthe chemical shift of syn-15e (see below). The mass spectrumshowed significant ions with masses corresponding to 15e�

or 16e� (m/z 1006, 40%) and [15e � Cl]� or [16e � Cl]�

(m/z 970, 100%). Diplatinum ions of the formal composition[2�15e � Cl]� or [2�16e � Cl]� (m/z 1977, 20%) were alsoevident.

The sample was chromatographed on alumina. The two leastpolar products were isolated as white powders in 31 and 7%yields, and characterized analogously to 11a–f. The massspectra indicated that both were monoplatinum species. Thefirst product exhibited a single 31P NMR signal, and sevenmethylene 13C NMR signals, whereas the second exhibited twomutually coupled 31P NMR signals and several additionalmethylene 13C NMR signals. Complexes of the type 15e canexist as two stereoisomers, differing in the relative orientationsof the phenyl groups (syn or anti). Accordingly, crystalstructures described below showed the products to be syn-15eand anti-15e, respectively. The contrasting NMR properties arefurther analyzed below.

3 Independent synthesis of an intraligand metathesis product

We wanted to be certain that the workups in Scheme 6 did notoverlook products derived from intraligand metathesis (14e,16e). Thus, an independent synthesis was sought. An initialring-closing metathesis of the free phosphine 4e was con-sidered. However, Grubbs’ catalyst 2 is not normally effectivewith alkenes that contain phosphines,12 and there are onlyscattered successes with Schrock-type catalysts.12b,13 In contrast,phosphines in which the lone pairs are protected with boraneare reliable substrates for alkene metatheses.12 Hence, thesequence summarized in Scheme 7 was investigated.

A potential problem was obvious at the outset. Reactions ofalkene-containing phosphines with borane sources can lead

either to protected phosphines or alkene hydroboration. Insome cases, the latter event can be circumvented by introducingthe alkene moieties subsequent to phosphorus protection.12a

Fortunately, the reaction of H3B�SMe2 and 4e at �20 �C gavethe target compound 17e in 65% yield. The 31P NMR spectrumshowed coupling to boron (1J(31P,11B) 75 Hz), and the 1H NMRspectrum exhibited a broad BH3 signal (1.0–0.2 ppm).

As illustrated in Scheme 7, ring-closing metathesis of 17ewith 2 gave the crude 15-membered cyclic phosphine derivative18e in 62–91% yields. Unlike the monomacrocyclizations inScheme 1, the mass spectrum exhibited ions correspondingboth to intramolecular and intermolecular metathesis products(18e�, m/z 315, 80%; formal composition [2�18e]�, m/z 629,20%). The 1H NMR spectrum showed three closely spaced mul-tiplets in the CH��CH region (ca. 1 : 1 : 1), consistent with amixture of E/Z isomers and/or intra/intermolecular products.

When 18e was subjected to the hydrogenation conditions inSchemes 1 and 6 (10% Pd/C, 1 atm H2), as well as higher H2

pressures (6 atm), no reaction occurred. Thus, 18e and H2

(6 atm) were combined in the presence of Wilkinson’s catalyst.Chromatography gave the saturated cyclic phosphine derivative19e in 77–74% yields. The 31P NMR spectrum showed onesignal (1J(31P,11B) 70 Hz), and the 13C NMR spectrum was muchsimpler than that of 19e. However, besides the seven expectedmethylene signals, several minor peaks were evident (<10%).The mass spectrum also showed, in addition to ions derivedfrom 19e, some diphosphorus species. Hence, the chromato-graphy conditions did not completely remove the materialderived from intermolecular metathesis.

As shown in Scheme 7, 19e was deprotected by a standardprocedure using HNEt2.

14 The crude cyclic phosphine

PPh(CH2)14 (20e) was directly reacted with the tetrahydro-thiophene complex 12. Chromatography gave the targetcomplex 16e in 24% overall yield from 19e. The mass spectrumexhibited only monoplatinum ions. The most intense peaksinvolved phosphine ligand loss, in contrast to syn-15e andanti-15e where no such fragments were observed. NMR spectrashowed no traces of any byproducts. The 31P signal (7.2 ppm)

1014 D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

Scheme 7 Synthesis of an authentic sample of 16e.

Fig. 1 Molecular structure of syn-15e.

was considerably upfield from those of syn-15e (11.8 ppm) andanti-15e (15.8, 11.2 ppm).

The 31P NMR spectrum of the crude hydrogenation productin Scheme 6 was reinvestigated. A small peak with a chemicalshift close to that of 16e was apparent. Integration allowed anupper limit of 2% to be placed upon the yield of 16e from 11e.The NMR tube was doped with a small amount of theindependently synthesized 16e to confirm that the chemicalshifts were identical. Finally, syn-15e, anti-15e, and 16e werecompared by alumina TLC (1 : 3 v/v CH2Cl2–hexanes). Rf

values of 0.56, 0.44, and 0.20 were found. Those of the variousbyproducts from Scheme 6 were much lower.

4 Structural and dynamic properties of syn-15e, anti-15e and 16e

The crystal structures of syn-15e and anti-15e were determinedas summarized in Table 1 and the experimental section.Key bond lengths, bond angles, and torsion angles are listed inTable 2.15 The two macrocycles in each compound are givenprimed and unprimed atom labels so that their features aremore easily compared. The molecular structure of syn-15e isdepicted in Fig. 1 and that of anti-15e in Fig. 2. The left viewsin Figs. 1 and 2 highlight the contrasting orientations ofthe phenyl rings with respect to the platinum square planes.The isomers also exhibit markedly different macrocycleconformations.

A C6H5/C6F5/C6H5 π stacking interaction is evident insyn-15e (Fig. 1). This feature is also found in the crystalstructures of 3c,e–g, (Scheme 1).3d It is now well established thatC6H5/C6F5 π interactions are attractive and a driving force

in many crystallizations.16 The average of the two centroid–centroid distances in syn-15e is 4.05 Å. This is somewhat greaterthan in 3e (3.60 Å), the related complex with only oneP(CH2)14P bridge. In contrast, anti-15e exhibits a single C6H5/C6F5 π interaction (Fig. 2). It is not as pronounced, with acentroid–centroid distance of 4.26 Å.

The crystal structure of 16e was similarly determined. Viewsthat highlight the trans relationship of the macrocyclic mono-phosphine ligands are given in Fig. 3. Selected metricalparameters are listed in Table 3. Like anti-15e, 16e exhibitsa single, somewhat weak C6H5/C6F5 π interaction, with acentroid–centroid distance of 4.49 Å.

The symmetry properties of syn-15e and anti-15e are relevantto several observations. As illustrated in Fig. 4, syn-15e hasidealized C2v symmetry. The phosphorus atoms and phenylrings are homotopic; they can be exchanged by a rotationaround the Cl–Pt–C6F5 axis. Each carbon atom of a givenmacrocycle has a homotopic counterpart in the other macro-cycle. In addition, the carbon atoms labeled Ca in Fig. 4 areenantiotopic with the carbon atoms labeled Cb. However, thegeminal protons of each methylene group are diastereotopic.

In contrast, anti-15e has C1 symmetry. As illustrated inFig. 4, both phosphorus atoms and phenyl rings arediastereotopic. The same holds for all carbon atoms of themacrocycles, as well as the geminal protons of the methylenegroups. Hence, the NMR spectra of anti-15e should be morecomplicated than those of syn-15e, in accord with observationsabove and additional details provided in the experimentalsection. For example, the 31P NMR spectrum of anti-15e showsan AB spin system, with distinct 1JPtP values for each signal.

1015D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

Table 1 General crystallographic data a

Complex syn-(E,E )-13c syn-15c syn-15e anti-15e 16a 16e

Formula C38H46ClF5P2Pt C38H50ClF5P2Pt C46H66ClF5P2Pt C46H66ClF5P2Pt C30H34ClF5P2Pt C46H66ClF5P2PtFormula weight 890.23 894.26 1006.47 1006.47 782.05 1006.47Crystal system Monoclinic Monoclinic Monoclinic Triclinic Orthorhombic TriclinicSpace group P21/n P21/c P21/c P1̄ Pbcn P1̄a/Å 13.64790(10) 23.5432(11) 24.8121(3) 11.69470(10) 18.5572(3) 10.57500(10)b/Å 19.0165(3) 15.7182(6) 10.5438(2) 13.29450(10) 10.9033(2) 12.2670(2)c/Å 15.0138(2) 21.5805(6) 18.0730(4) 14.9666(2) 28.7856(5) 18.1630(3)α/� 90 90 90 88.3340(10) 90 72.9290(9)β/� 106.7190(10) 112.273(2) 104.6070(10) 81.1850(10) 90 84.6100(8)γ/� 90 90 90 76.1950(10) 90 82.4310(8)V/Å3 3731.89(8) 7390.2(5) 4575.32(14) 2232.96(4) 5824.33(17) 2228.93(6)Z 4 8 4 2 8 2Dc/Mg m�3 1.584 1.607 1.461 1.495 1.784 1.500µ/mm�1 3.968 4.008 3.246 3.325 5.071 3.331F(000) 1776 3584 2048 1022 3072 1024Crystal size/mm 0.35 × 0.20 × 0.20 0.10 × 0.10 × 0.10 0.30 × 0.20 × 0.10 0.1 × 0.1 × 0.1 0.30 × 0.20 × 0.20 0.20 × 0.20 × 0.10θ Limit/� 1.89–27.48 1.60–25.02 2.11–27.51 1.38–25.05 1.41–27.48 2.21–27.52Index ranges hkl �17 to 17, �24 to 24,

�19 to 19�27 to 28, �18 to 18,�24 to 25

�31 to 32, �12 to 13,�23 to 23

�13 to 13, �15 to 15,�17 to 17

�24 to 24, �14 to 14,�37 to 37

�13 to 13, �15 to 15,�23 to 23

Reflections collected 16508 43886 17699 15379 12286 19533Independent reflections 8549 13024 10322 7900 6642 10238Reflections [I > 2σ(I )] 7851 6875 7022 7011 5538 9428Data/restraints/parameters 8549/0/424 13024/0/847 10322/0/496 7900/0/496 6642/0/352 10238/0/496Goodness-of-fit on F 2 1.061 0.930 0.998 1.152 1.116 1.029Final R indices [I >2σ(I )] R1 = 0.0199, wR2 = 0.0491 R1 = 0.0449, wR2 = 0.0958 R1 = 0.0404, wR2 = 0.0695 R1 = 0.0247, wR2 = 0.0601 R1 = 0.0240, wR2 = 0.0602 R1 = 0.0268, wR2 = 0.0621R Indices (all data) R1 = 0.0233, wR2 = 0.0505 R1 = 0.1156, wR2 = 0.1319 R1 = 0.0860, wR2 = 0.0796 R1 = 0.0324, wR2 = 0.0751 R1 = 0.0334, wR2 = 0.0751 R1 = 0.0305, wR2 = 0.0636Largest diff. peak and

hole ∆ρ/e Å�30.997 and �0.966 0.894 and �1.307 2.621 and �1.408 1.371 and �0.978 0.893 and �0.996 1.431 and �0.920

a Data common to all structures: diffractometer, Nonius Kappa CCD; wavelength, 0.71073 Å; temperature, 173(2) K.

10

16

Da

lto

n T

ra

ns

.,2

00

4, 1

01

2–

10

28

Table 2 Key bond lengths, bond angles, and torsion angles for interligand metathesis products

syn-15c

Complex syn-(E,E )-13c First molecule a Second molecule a syn-15e anti-15e

Bond lengths (Å)

Pt–P(1)/Pt–P(2) 2.3064(6)/2.2984(6) 2.313(2)/2.303(2) 2.323(2)/2.318(3) 2.3139(11)/2.3075(11) 2.2970(10)/2.2986(9)Pt–Cl 2.3671(5) 2.377(2) 2.380(3) 2.3778(11) 2.3560(10)Pt–C(30) 2.015(2) 1.989(10) 2.005(11) 2.002(4) 2.017(4)C(1)–C(2)/C(1�)–C(2�) 1.531(3)/1.533(3) 1.526(14)/1.522(14) 1.529(13)/1.520(17) 1.515(6)/1.540(5) 1.522(6)/1.522(5)C(2)–C(3)/C(2�)–C(3�) 1.523(3)/1.528(3) 1.532(14)/1.569(18) 1.517(13)/1.533(17) 1.518(6)/1.514(6) 1.533(7)/1.532(6)C(3)–C(4)/C(3�)–C(4�) 1.530(3)/1.530(4) 1.508(15)/1.345(19) 1.491(14)/1.536(18) 1.518(6)/1.504(6) 1.503(8)/1.513(7)C(4)–C(5)/C(4�)–C(5�) 1.493(4)/1.502(4) 1.505(14)/1.471(16) 1.558(15)/1.497(17) 1.520(6)/1.516(6) 1.508(7)/1.520(6)C(5)–C(6)/C(5�)–C(6�) 1.316(4)/1.314(4) 1.523(13)/1.526(16) 1.430(17)/1.513(17) 1.518(7)/1.521(6) 1.519(8)/1.522(7)C(6)–C(7)/C(6�)–C(7�) 1.492(4)/1.502(4) 1.502(13)/1.490(15) 1.565(15)/1.506(15) 1.509(7)/1.534(6) 1.489(8)/1.513(6)C(7)–C(8)/C(7�)–C(8�) 1.526(4)/1.529(4) 1.525(15)/1.509(16) 1.470(16)/1.494(15) 1.515(7)/1.505(7) 1.530(8)/1.525(6)C(8)–C(9)/C(8�)–C(9�) 1.525(3)/1.521(3) 1.504(14)/1.456(16) 1.549(14)/1.497(15) 1.547(6)/1.545(7) 1.548(7)/1.521(6)C(9)–C(10)/C(9�)–C(10�) 1.524(3)/1.530(3) 1.533(14)/1.500(15) 1.515(15)/1.484(16) 1.515(6)/1.531(7) 1.524(7)/1.523(6)C(10)–C(11)/C(10�)–C(11�) – – – 1.520(6)/1.508(6) 1.509(7)/1.513(6)C(11)–C(12)/C(11�)–C(12�) – – – 1.518(6)/1.508(6) 1.511(7)/1.515(6)C(12)–C(13)/C(12�)–C(13�) – – – 1.513(6)/1.528(6) 1.521(6)/1.517(6)C(13)–C(14)/C(13�)–C(14�) – – – 1.526(6)/1.525(6) 1.527(6)/1.529(5)

Bond angles (�)

C(30)–Pt–P(1) 94.00(6) 94.6(3) 89.4(3) 90.47(12) 93.31(10)C(30)–Pt–P(2) 91.50(6) 91.3(3) 93.1(3) 91.51(12) 87.42(10)P(1)–Pt–P(2) 174.41(2) 172.21(10) 173.96(11) 177.99(4) 173.33(3)C(30)–Pt–Cl 178.06(6) 178.3(3) 179.3(3) 178.89(13) 175.18(11)P(1)–Pt–Cl 84.062(19) 86.83(9) 90.42(10) 88.89(4) 86.71(3)P(2)–Pt–Cl 90.44(2) 87.37(9) 86.94(9) 89.14(4) 93.12(3)

Torsion angles (�)

P(2)–Pt–P(1)–C(1)/P(2)–Pt–P(1)–C(1�) 45.2(2)/–70.5(2) 19.8(9)/–95.2(8) �22.4(11)/–139.9(10) �69.1(12)/49.8(12) 90.3(3)/–145.5(3)Pt–P(1)–C(1)–C(2)/Pt–P(1)–C(1�)–C(2�) 35.56(19)/–50.42(19) 59.0(8)/–70.8(9) 47.8(9)/51.5(11) 46.5(4)/56.5(3) �160.1(3)/–44.7(3)P(1)–C(1)–C(2)–C(3)/P(1)–C(1�)–C(2�)–C(3�) �176.85(17)/179.15(18) 176.6(7)/69.1(12) �157.9(8)/–94.5(13) �175.3(3)/–164.6(3) 172.5(3)/161.9(3)C(1)–C(2)–C(3)–C(4)/C(1�)–C(2�)–C(3�)–C(4�) 172.4(2)/–75.0(3) 60.8(12)/156.7(16) 179.6(9)/172.6(11) 178.8(4)/–180.0(4) �54.1(5)/�174.3(3)C(2)–C(3)–C(4)–C(5)/C(2�)–C(3�)–C(4�)–C(5�) �64.2(3)/–67.6(3) 53.5(13)/174.3(13) �67.6(14)/172.8(12) �176.7(4)/–177.4(4) �59.0(5)/60.7(5)C(3)–C(4)–C(5)–C(6)/C(3�)–C(4�)–C(5�)–C(6�) 131.5(3)/129.7(3) 52.8(14)/83.8(19) 107.7(13)/45.1(16) �170.2(4)/–176.5(4) 178.1(4)/56.0(5)C(4)–C(5)–C(6)–C(7)/C(4�)–C(5�)–C(6�)–C(7�) �175.2(2)/179.4(2) 170.5(9)/–157.9(13) 177.0(10)/60.4(15) �51.7(6)/–60.6(7) 179.6(4)/169.1(4)C(5)–C(6)–C(7)–C(8)/C(5�)–C(6�)–C(7�)–C(8�) 118.4(3)/132.5(3) 56.0(13)/97.0(14) 59.4(15)/–169.9(11) �62.1(6)/–67.0(7) 71.5(6)/–175.8(4)C(6)–C(7)–C(8)–C(9)/C(6�)–C(7�)–C(8�)–C(9�) �66.7(3)/–68.5(3) 53.6(14)/–58.9(15) 57.9(15)/–166.1(11) �179.6(4)/–176.7(4) 75.9(6)/–179.1(4)C(7)–C(8)–C(9)–C(10)/C(7�)–C(8�)–C(9�)–C(10�) 179.6(2)/166.0(2) �179.1(8)/176.0(11) �174.7(10)/–61.8(15) �61.9(6)/–60.5(7) �167.7(4)/72.4(5)C(8)–C(9)–C(10)–C(11)/C(8�)–C(9�)–C(10�)–C(11�) – – – �59.7(6)/–50.4(7) �173.7(4)/72.9(5)C(9)–C(10)–C(11)–C(12)/C(9�)–C(10�)–C(11�)–C(12�) – – – �178.6(4)/–171.3(4) �167.2(4)/–177.4(3)C(10)–C(11)–C(12)–C(13)/C(10�)–C(11�)–C(12�)–C(13�) – – – 176.3(4)/–170.4(4) 73.8(5)/62.0(5)C(11)–C(12)–C(13)–C(14)/C(11�)–C(12�)–C(13�)–C(14�) – – – �179.1(4)/–174.0(4) 75.0(5)/51.8(5)C(n � 2)–C(n � 1)–C(n)–P(2)/C(n� � 2)–C(n� � 1)–C(n�)–P(2) b 175.99(19)/–163.28(17) 154.6(7)/–168.0(9) 169.8(7)/–69.7(13) �169.7(3)/–172.2(3) 177.4(3)/–179.7(3)C(n � 1)–C(n)–P(2)–Pt/C(n� � 1)–C(n�)–P(2)–Pt b 42.9(2)/53.70(18) �44.2(8)/36.9(11) �48.2(9)/82.7(9) 56.0(4)/39.2(4) 53.6(3)/167.6(3)C(n)–P(2)–Pt–P(1)/C(n�)–P(2)–Pt–P(1) b �74.4(2)/43.0(2) �11.6(9)/102.2(8) 8.6(12)/121.2(10) 28.1(12)/�91.9(12) �23.4(3)/96.9(3)a Independent molecules in the unit cell. b n = Number of carbons in macrocycle.

10

17

Da

lto

n T

ra

ns

.,2

00

4, 1

01

2–

10

28

Fig. 2 Molecular structure of anti-15e.

Fig. 3 Molecular structure of 16e.

Scheme 8 Ring-closing metathesis/hydrogenation sequence for 11a.

A toluene-d8 solution of anti-15e was warmed to 95 �C while31P NMR spectra were periodically recorded. No coalescenceor significant broadening of the 31P NMR signals was noted,and no new peaks derived from syn-15e or other species

Fig. 4 Idealized structures and stereochemical relationships in 15.

appeared. Application of the coalescence formula,17 using the∆ν and J values for the phosphorus atoms from the low tem-perature limit (618.2 and 426.8 Hz, 25 �C), allowed a lower limitof 16.4 kcal mol�1 (95 �C) to be placed on any process capableof rendering the phosphorus atoms of anti-15e equivalent. Onesuch possibility, which should become accessible with longerP(CH2)nP bridges, is analyzed in the discussion section.

5 Ring-closing metatheses of 11a,b,c,d,f

Complex 11a, which features short (CH2)2 segments betweenthe phosphorus and terminal alkenyl moieties, would be a veryunlikely candidate for interligand metathesis, or cyclizationmode II in Scheme 2. The trans phosphorus atoms would bebridged by only six carbon atoms, resulting in a highly strainednine-membered ring. The shortest known saturated bridgebetween trans phosphorus atoms in a square planar complexconsists of nine methylene groups, giving a twelve-memberedring.6,18

As shown in Scheme 8, 11a (0.0093 M) and 2 were combinedunder conditions analogous to those in Schemes 1 and 6.Workup gave the expected intraligand metathesis product,bis(monophosphine) complex (Z,Z )-14a, in 86% yield.

1018 D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

Table 3 Key bond lengths, bond angles, and torsion angles for intraligand metathesis products

Complex 16a 16e

Bond lengths (Å)

Pt–P(1)/Pt–P(2) 2.3129(9)/2.3056(9) 2.2972(7)/2.3049(7)Pt–Cl 2.3660(8) 2.3554(7)Pt–C(30) 2.017(3) 2.017(3)C(1)–C(2)/C(1�)–C(2�) 1.527(6)/1.537(5) 1.535(4)/1.533(4)C(2)–C(3)/C(2�)–C(3�) 1.510(7)/1.516(6) 1.520(4)/1.515(5)C(3)–C(4)/C(3�)–C(4�) 1.513(7)/1.533(6) 1.530(5)/1.512(6)C(4)–C(5)/C(4�)–C(5�) 1.523(5)/1.527(6) 1.519(5)/1.564(9)C(5)–C(6)/C(5�)–C(6�) 1.540(5)/1.530(5) 1.524(5)/1.291(11) b

C(6)–C(7)/C(6�)–C(7�) – 1.522(5)/1.428(11) b

C(7)–C(8)/C(7�)–C(8�) – 1.517(6)/1.388(9) b

C(8)–C(9)/C(8�)–C(9�) – 1.562(6)/1.578(8)C(9)–C(10)/C(9�)–C(10�) – 1.504(5)/1.487(7)C(10)–C(11)/C(10�)–C(11�) – 1.513(6)/1.554(8)C(11)–C(12)/C(11�)–C(12�) – 1.503(5)/1.531(6)C(12)–C(13)/C(12�)–C(13�) – 1.528(5)/1.524(5)C(13)–C(14)/C(13�)–C(14�) – 1.541(4)/1.532(4)

Bond angles (�)

C(30)–Pt–P(1)/C(30)–Pt–P(2) 91.23(9)/93.41(9) 93.69(7)/87.72(7)P(1)–Pt–P(2) 174.84(3) 175.54(3)C(30)–Pt–Cl 177.99(10) 177.52(8)P(1)–Pt–Cl/P(2)–Pt–Cl 86.85(3)/88.53(3) 86.39(3)/92.38(3)

Torsion angles (�)

P(2)–Pt–P(1)–C(1)/P(1)–Pt–P(2)–C(1�) 32.9(4)/–170.9(4) �104.1(3)/77.9(3)Pt–P(1)–C(1)–C(2)/Pt–P(2)–C(1�)–C(2�) �152.5(3)/–49.7(3) �176.24(18)/–170.6(2)P(1)–C(1)–C(2)–C(3)/P(2)–C(1�)–C(2�)–C(3�) 63.4(5)/–33.1(4) �166.7(2)/–173.1(3)C(1)–C(2)–C(3)–C(4)/C(1�)–C(2�)–C(3�)–C(4�) �94.9(5)/–49.2(5) �177.8(3)/–57.8(5)C(2)–C(3)–C(4)–C(5)/C(2�)–C(3�)–C(4�)–C(5�) 39.1(5)/94.8(4) �54.3(4)/–55.5(5)C(3)–C(4)–C(5)–C(6)/C(3�)–C(4�)–C(5�)–C(6�) 50.0(5)/–72.3(4) �54.9(4)/–148.0(9)C(4)–C(5)–C(6)–C(7)/C(4�)–C(5�)–C(6�)–C(7�) – 178.3(3)/–162.0(2)C(5)–C(6)–C(7)–C(8)/C(5�)–C(6�)–C(7�)–C(8�) – �169.2(3)/–60.6(14)C(6)–C(7)–C(8)–C(9)/C(6�)–C(7�)–C(8�)–C(9�) – 60.5(5)/77.8(11)C(7)–C(8)–C(9)–C(10)/C(7�)–C(8�)–C(9�)–C(10�) – 52.3(5)/56.7(9)C(8)–C(9)–C(10)–C(11)/C(8�)–C(9�)–C(10�)–C(11�) – 170.6(3)/171.8(5)C(9)–C(10)–C(11)–C(12)/C(9�)–C(10�)–C(11�)–C(12�) – 57.5(4)/61.9(5)C(10)–C(11)–C(12)–C(13)/C(10�)–C(11�)–C(12�)–C(13�) – 53.5(5)/58.1(5)C(11)–C(12)–C(13)–C(14)/C(11�)–C(12�)–C(13�)–C(14�) – 52.9(4)/–179.9(3)C(n � 2)–C(n � 1)–C(n)–P(1)/C(n � 2�)–C(n � 1�)–C(n�)–P(2) a �92.7(4)/59.1(4) 161.3(2)/171.4(2)C(n � 1)–C(n)–P(1)–C(1)/C(n � 1�)–C(n�)–P(2)–C(1�) a 54.1(3)/–70.6(3) 50.3(2)/–46.1(3)C(n)–P(1)–C(1)–C(2)/C(n�)–P(2)–C(1�)–C(2�) a �30.9(4)/79.2(3) 57.0(3)/–63.1(2)Pt–P(1)–C(n)–C(n � 1)/Pt–P(2)–C(n�)–C(n � 1�) a 174.5(2)/61.5(3) �79.9(2)/63.0(2)P(2)–Pt–P(1)–C(n)/P(1)–Pt–P(2)–C(n�)a �86.4(4)/65.5(4) �133.0(3)/–42.3(4)

a n = Number of methylene groups in macrocycle. b The thermal ellipsoids for C(5�) to C(8�) are very elongated.

Fig. 5 Molecular structure of 16a.

Hydrogenation as in Schemes 1 and 6 gave 16a in 64% yieldafter workup. The crystal structure was determined as sum-marized in Table 1 and the experimental section. Metricalparameters are listed in Table 3. The molecular structure isdepicted in Fig. 5. There is a single C6H5/C6F5 π interaction,with a centroid–centroid distance of 3.58 Å.

Complex 11b, which could cyclize to an eleven-memberedinterligand metathesis product or a nine-membered intraligandmetathesis product, was similarly combined with 2. However,no tractable products could be isolated, even when reactionswere conducted at higher dilution (0.0033 M). Complex 11cgave similar results in comparable concentration ranges. How-

1019D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

Scheme 9 Ring-closing metathesis/hydrogenation sequence for 11c.

Fig. 6 Molecular structure of syn-(E,E )-13c (top left and right) and syn-15c (bottom left, first independent molecule; bottom right, secondindependent molecule).

ever, when 0.00067 M solutions were used as shown in Scheme 9,a monoplatinum product could be isolated in 21% yield. Acrystal structure established the formation of the intraligandmetathesis product syn-(E,E )-13c.19 The molecular structureis depicted in Fig. 6 (top), and metrical parameters are listed inTable 2.

Hydrogenation of syn-(E,E )-13c gave the saturated analogsyn-15c in 95% yield. The crystal structure of this compound, alower homolog of syn-15e (Fig. 1), was similarly determined.The unit cell contained two independent molecules. Asillustrated in Fig. 6 (bottom), they differ in the macro-cycle conformations. Both syn-(E,E )-13c and syn-15cexhibit C6H5/C6F5/C6H5 π stacking interactions, with averagecentroid–centroid distances of 4.16 and 3.85–3.94 Å, respect-ively. They also give a single 31P NMR signal, as expected forsyn isomers from the analysis in Fig. 4. The ring-closingmetathesis of 1c (Scheme 1), which yields a P(CH2)4CH��CH(CH2)4P bridge as in syn-(E,E )-13c, gives a 93 : 7 mixture ofE/Z isomers.

Since 11d contains a longer methylene segment and inter-ligand metathesis would generate a presumably less strainedfifteen-membered ring, enhanced selectivity for cyclizationmode II was expected. However, only very small amountsof non-oligomeric products could be isolated, even when0.0019 M solutions of 11d were treated with 2. As shown inScheme 10, the crude reaction mixture was directly hydro-

genated. Chromatography gave syn-15d in 5% overall yield.19

The syn stereochemistry was assigned based upon NMRproperties as described above. Although a crystal structurecould not be solved, the data were of sufficient quality toexclude the intraligand metathesis product 16d. Also, no ionsderived from loss of a monophosphine ligand were evident inthe mass spectrum.

Scheme 10 Ring-closing metathesis/hydrogenation sequences for11d,f.

1020 D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

Fig. 7 Some representative conformations of 11 for interligand metathesis.

Given the yield trends in Scheme 1, it was thought that 11fand 11e might give comparable amounts of interligandmetathesis products. As shown in Scheme 10, the reactionof 11f (0.0033 M) and 2 was followed by hydrogenation.Chromatography gave syn-15f in 14% overall yield.19 Otherfractions gave material with 31P NMR signal patterns suggestiveof anti-15f, but samples could not be purified. Since it has notyet been possible to crystallographically characterize syn-15f, aremote possibility remains that it might be the intraligandmetathesis product 16f. However, the complexes assigned assyn-15c,d,e,f exhibit several monotonic trends (e.g., 31P NMR16.2, 12.5, 11.8, 10.8 ppm; JPPt 2612, 2590, 2560, 2551 Hz), inaccord with a homologous series.

Discussion

1 Scope and efficiency of macrocyclizations

Schemes 6, 9 and 10 establish that complexes of doubly trans-spanning diphosphine ligands are easily accessed by alkenemetatheses. Although the yields are modest, advanced gener-ation metathesis catalysts may help in certain cases,19 and otherroutes would require many additional steps. Such complexes areto our knowledge unknown. However, as shown in Scheme 11, aconceptually related doubly trans-spanning bis(pyridine) com-plex has also been accessed by alkene metathesis.20 In the educt21, each pyridine nitrogen is flanked by two ortho homoallylgroups. These would be expected to extend above and below thepalladium square plane, preorganizing the alkenyl moietiesfor interligand metathesis. Accordingly, 22 is isolated in 80%yield. Hence, alkene metathesis may prove to be a general routeto metalladimacrocycles of the type II (Scheme 2), albeit invariable yields.

In earlier papers, we have argued that alkene metatheses inmetal coordination spheres are often aided by some analog ofthe “geminal dialkyl effect”.21 A PPh2, MPPh, or similar groupmight play a role analogous to a CR2 group in making gaucheconformations of four-atom segments energetically more com-petitive with anti conformations. When only anti linkages arepresent, the termini of α,ω-difunctionalized systems cannotapproach one another. Shaw and co-workers have furthermorestudied reactions of diphosphines R2P(CH2)nPR2 and squareplanar complexes that lead to trans substitution products.18

They find that the ratio of monometallic to di- and polymetallic

Scheme 11 A doubly trans-spanning bis(pyridine) complex.

products dramatically increases with the size of the phosphorussubstituent.

The PPh2 and PPhR units in our platinum complexespromote gauche conformations in the solid state, as describedbelow. However, for the monomacrocyclizations of 1 inScheme 1, we see no obvious factor that should direct thealkenyl moieties on the same sides of the platinum squareplane. Also, no axial bonding interactions involving pendantor bridging C��C (or C���C) 22 moieties have ever been observed(e.g., syn-(E,E )-13c, Fig. 6). Nonetheless, the yields of intra-molecular metathesis products are not much lower than with21, which as noted above is geometrically predisposed to cycliz-ation. The new data in this paper do not offer additional insighton this point, and pose several further questions, such as: (i)why is intraligand metathesis (III, Scheme 2) disfavored inSchemes 6, 9 and 10? (ii) why do the yields of monoplatinuminterligand metathesis products drop relative to Scheme 1,despite comparable dilution levels? In analyzing these issues, wepresume that our product mixtures are under kinetic control.19

Appreciable quantities of intraligand metathesis productsare found only with 11a (Scheme 8), for which interligandmetathesis is impossible. Complex 11b, for which interligandmetathesis would also be unlikely, gives exclusively inter-molecular metathesis. Perhaps intraligand metathesis, whichwould give a nine-membered cyclic phosphine ligand, iskinetically less favorable than with 11a, allowing bimolecularcondensations to compete. However, with 11c,d,e,f, all of whichgive at least some intramolecular metathesis, we have no ration-ale for the absence of intraligand cyclization. Note that highyields of fifteen-membered cyclic phosphine complexes areobtained by intraligand metathesis in Scheme 3.

Given that intraligand metathesis is not very rapid with11c,d,e,f, why are the yields of interligand metathesis productslower than in Scheme 1? Fig. 7 shows two representativeconformations of 11 (VI, VII) as viewed down the phosphorus–carbon bond axes, the energies of which should be nearly equal.The chlorine and C6F5 ligands can be visualized as directlybehind and in front of the “Pt”. In both cases, gauchePt–PPhR–CH2–CH2 conformations are used to direct two(CH2)nCH��CH2 moieties on the same side of the platinumsquare plane, and in orientations that are favorable forinterligand metathesis. Many other conformations are possiblethat are to varying degrees less favorable for macrocyclization,as analyzed elsewhere.23

Importantly, VI can only lead to syn isomers of 13, whereasVII can only lead to anti isomers. Hence, the syn/anti stereo-chemistry is set by the first metathesis. Furthermore, in themacrocycle resulting from VII, the two remaining (CH2)n-CH��CH2 moieties will be directed on opposite sides of theplatinum square plane, an orientation unfavorable for intra-molecular metathesis. Thus, bimolecular condensations shouldbe more competitive, and more oligomeric products shouldarise from this manifold. This would result in lower yields ofmonoplatinum interligand metathesis products. Accordingly,only in the case of 15e is an anti isomer isolated. Finally, wenote in passing that it might be easier to incorporate a C6H5/

1021D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

C6F5/C6H5 π stacking interaction into the transition statederived from VI.

2 Macrocycle structures

Various crystallographic features are relevant to phenomenaanalyzed above. First, the interligand metathesis productsin Table 2 have bond lengths and angles about platinum similarto those of the intraligand metathesis products in Table 3.The P–Pt–P bond angles (177.99(4)–172.21(10)� vs. 175.54(3)–174.84(3)�) might have contracted if the ring strain associatedwith the trans-spanning ligands were significant.

Consider the torsion angle patterns of the complexes in Table2 next. With syn-15e, the macrocycles are homologous. Allfour Pt–PPh–CH2–CH2 segments (Pt–P(1)–C(1)–C(2), C(13)–C(14)–P(2)–Pt, and primed analogs) exhibit gauche conform-ations with torsion angles of 46.5/56.5� and 56.0/39.2�. Thisis in accord with an analog of a “germinal dialkyl effect” asdiscussed in the previous section, and as exploited in the cycliz-ation-favorable conformations in Fig. 7. All of the macrocyclesin Scheme 1 (3c,e,f,g) crystallize similarly. The four PPh–CH2–CH2–CH2 segments in syn-15e exhibit anti conformations, withtorsion angles of �175.3/�164.6� and �169.7/�172.2�. Thethree subsequent four-carbon sequences in each ring also showanti conformations. However, of the five remaining four-carbonsequences, four exhibit gauche conformations, with torsionangles of �51.7/�60.6�, �62.1/�67.0�, �61.9/�60.5�, and�59.7/�50.4�.

The torsion angle patterns of the macrocycles in anti-15e arenot homologous, and differ significantly from those of syn-15e.One of the two Pt–PPh–CH2–CH2 segments in each ring nowexhibits a gauche conformation (C(13)–C(14)–P(2)–Pt �53.6�;Pt–P(1)–C(1�)–C(2�) �44.7�), while the other remains anti(�160.1�, 167.6�). All PPh–CH2–CH2–CH2 sequences againshow anti conformations. However, now there are six four-carbon gauche segments in each ring, for a total of seven gauchemoieties – one more than in each ring of syn-15e. Although anensemble of accessible conformations would be expected insolution, this suggests (in the absence of non-bonded inter-actions) that anti-15e is more highly strained. As summarizedin Table 3, each fifteen-membered ring in the constitutionalisomer 16e exhibits seven four-carbon gauche segments.Furthermore, all C(13)–C(14)–P–C(1) and C(14)–P–C(1)–C(2)sequences have gauche conformations (50.3/�46.1�, 57.0/�63.1�), consistent with a PPhPt-based “geminal dialkyleffect”.

Complex syn-15c, with two thirteen-membered rings, crystal-lizes with two independent molecules in the unit cell. Althoughnone of the torsion angle patterns are homologous, all eightPt–PPh–CH2–CH2 segments exhibit gauche conformations,with torsion angles of ±36.9� to ±82.7�. Two of the fourrings exhibit three additional gauche PPh–CH2–CH2–CH2 orfour-carbon segments, and the other rings exhibit four andfive. The unsaturated analog syn-(E,E )-13c also crystallizeswith gauche Pt–PPh–CH2–CH2 segments. One ring featuresonly two additional gauche segments, and the other three (four-carbon in each case). The Z C��C moiety enforces one antilinkage.

A final structural issue involves the size relationship betweenthe macrocycle and the other ligands on platinum. Considerfirst 3e (Scheme 1), which has a single trans-spanning P(CH2)14Pbridge. A 180� rotation of the Cl–Pt–C6F5 moiety, with thesmaller chlorine ligand passing under the bridge, is rapid onthe NMR time scale and renders diastereotopic groups equiv-alent.3d In 3c, which has a shorter P(CH2)10P bridge, therotational barrier becomes much higher and separate NMRsignals for diastereotopic groups are observed. As can bevisualized from V in Fig. 4, analogous 180� rotations would alsoexchange the diastereotopic phosphorus atoms of anti-15e.However, since there are now two P(CH2)14P bridges, the larger

C6F5 group must also be able to pass under the methylenechain.

The distance from the platinum to the para fluorine atom inanti-15e is 6.18 Å. This is nearly as great as the distance fromplatinum to the most remote macrocyclic carbons (7.19/6.85 Å).When the van der Waals radius of fluorine (1.47 Å) is added tothe former value, and the van der Waals radius of carbon (1.70Å) is subtracted from the latter values,24 it is obvious that the“vehicle height” is much greater than the “bridge height”(7.65 Å vs. 5.49/5.15 Å). Accordingly, two 31P NMR signals areobserved. However, with still longer methylene bridges, rotationof the Cl–Pt–C6F5 moiety should become possible, leading todynamic NMR phenomena.

3 Summary and prospective

Architecturally novel doubly trans-spanning diphosphinecomplexes are easily accessed by interligand alkene metathesesof the bis(phosphine) complexes 11c,d,e,f (Schemes 6, 9 and10). Although the yields are lower than those of the singlytrans-spanning diphosphine complexes obtained from 1c,e,f,g(Scheme 1), advanced-generation metatheses catalysts mayoffer improvements.19 In any event, conventional syntheseswould require many additional steps. Curiously, intraligandmetathesis products are observed only when the carbon bridgeswould be too short to span trans positions (Scheme 8). Oneattempt to extend these reactions to still more complex eductsthat can lead to higher polycycles was disappointing (Scheme4). However, as will be described in future papers, othershave been spectacularly successful.25 Taken together, theseinvestigations – as well as clever findings by others 2,5 – aresignificantly advancing the utility of alkene metatheses insyntheses of topologically unusual inorganic and organo-metallic systems.

Experimental

General data

All reactions were conducted under N2 (or H2) atmospheres.Chemicals were treated as follows: THF, ether, benzene, andtoluene, distilled from Na/benzophenone; CH2Cl2, distilledfrom CaH2 (for reactions) or simple distillation (chromato-graphy); hexanes and ethanol, simple distillation; HNEt2,distilled from NaOH; CDCl3, ClCH2CH2Cl (99%, Fluka),Ru(��CHPh)(PCy3)2(Cl)2 (2, Strem), H3B�SMe2 (Fluka, 99%),Rh(PPh3)3(Cl) (Strem), 10% Pd/C (Lancaster or Acros), PPhH2

(99%, Strem), n-BuLi (Acros, 2.5 M in hexanes), Br(CH2)nCH��CH2 (n = 2, 98%, Fluka; 3, 95%, Aldrich; 4, 90%, Fluka; 5, 97%,Aldrich), used as received.

NMR spectra were obtained on Bruker or Jeol 400 MHzspectrometers. IR and mass spectra were recorded on ASIReact-IR 1000 and Micromass Zabspec instruments, respect-ively. DSC and TGA data were obtained with a Mettler-ToledoDSC-821 instrument.26 Microanalyses were conducted with aCarlo Erba EA1110 instrument (in-house).

PPh((CH2)2CH��CH2)2 (4a) 7

A Schlenk flask was charged with PPhH2 (0.514 g, 4.67 mmol)and THF (20 mL) and cooled to 0 �C. Then n-BuLi (2.5 M inhexanes, 3.75 mL, 9.4 mmol) was added dropwise with stirringover 10 min. The colorless solution turned yellow–orange. After5 min, Br(CH2)2CH��CH2 (0.95 mL, 9.4 mmol) was added. Thesolution became colorless. The cold bath was removed. After3.5 h, solvent was removed by oil-pump vacuum. The residuewas filtered through a silica plug (5 cm) with hexanes–toluene(1 : 1 v/v). The filtrate was taken to dryness by oil-pumpvacuum to give 4a (0.916 g, 4.20 mmol, 90%) as a colorlessoil. Calc. for C14H19P: C, 77.06; H, 8.72. Found: C, 77.54; H,9.51%.

1022 D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

NMR: 27 1H 7.56–7.52 (m, 2 H of Ph), 7.37 (m, 3 H of Ph),5.92–5.82 (m, 2 H, 2CH��), 5.05–4.96 (m, 4 H, 2 ��CH2), 2.17–2.10 (m, 4 H, 2CH2), 1.85–1.79 (m, 4 H, 2CH2);

13C{1H} 28 139.3(d, JCP = 11.9, CH��), 138.4 (d, 1JCP = 14.7, i-Ph), 132.9 (d, 2JCP =18.8, o-Ph), 129.3 (s, p-Ph), 128.8 (d, 3JCP = 7.0, m-Ph), 114.8 (s,��CH2), 30.4 (d, JCP = 14.8, CH2), 27.8 (d, JCP = 11.9, CH2);31P{1H} �23.0 (s).

PPh((CH2)3CH��CH2)2 (4b) 8

PPhH2 (0.685 g, 6.23 mmol), THF (20 mL), n-BuLi (2.5 M inhexanes, 5.0 mL, 12.5 mmol) and Br(CH2)3CH��CH2 (1.48 mL,12.5 mmol) were combined in a procedure analogous to that for4a. An identical workup gave 4b (1.41 g, 5.73 mmol, 92%) as acolorless oil.

NMR: 27 1H 7.55–7.51 (m, 2 H of Ph), 7.38–7.35 (m, 3 H ofPh), 5.81–5.73 (m, 2 H, 2CH��), 5.04–4.96 (m, 4 H, 2 ��CH2),2.17–2.12 (m, 4 H, 2CH2), 1.76–1.70 (m, 4 H, 2CH2), 1.54–1.48(m, 4 H, 2CH2);

13C{1H} 28 138.8 (d, 1JCP = 15.0, i-Ph), 138.4 (s,CH��), 132.6 (d, 2JCP = 18.3, o-Ph), 128.9 (s, p-Ph), 128.5 (d, 3JCP

= 7.0, m-Ph), 115.0 (s, ��CH2), 35.4 (d, JCP = 11.8, CH2), 27.8 (d,JCP = 10.8, CH2), 25.4 (d, JCP = 14.3, CH2);

31P{1H} �23.5 (s).

PPh((CH2)4CH��CH2)2 (4c)

PPhH2 (0.572 g, 5.20 mmol), THF (20 mL), n-BuLi (2.5 M inhexanes, 4.2 mL, 10.5 mmol) and Br(CH2)4CH��CH2 (1.4 mL,10.4 mmol) were combined in a procedure analogous to that for4a. An identical workup gave 4c (1.27 g, 4.63 mmol, 89%) as acolorless oil. Calc. for C18H27P: C, 78.83; H, 9.85. Found C,79.11; H, 10.04%.

NMR: 27 1H 7.44 (m, 2 H of Ph), 7.26 (m, 3 H of Ph), 5.67 (m,2 H, 2CH��), 4.86 (m, 4 H, 2 ��CH2), 1.98–1.91 (m, 4 H, 2CH2),1.64–1.59 (m, 4 H, 2CH2), 1.42–1.29 (m, 8 H, 4CH2);

13C{1H} 28

139.1 (s, CH��), 138.6 (d, 1JCP = 16.0, i-Ph), 132.7 (d, 2JCP = 19.0,o-Ph), 129.1 (s, p-Ph), 128.7 (d, 3JCP = 7.0, m-Ph), 114.8(s, ��CH2), 33.8 (s, CH2), 30.8 (d, JCP = 11.0, CH2), 28.4 (d, JCP =11.0, CH2), 25.8 (d, JCP = 13.0, CH2);

31P{1H} �23.0 (s).MS: 29 275 (4c�, 100%), 192 ([4c � (CH2)4CH��CH2]

�, 92%).

PPh((CH2)5CH��CH2)2 (4d)

PPhH2 (0.606 g, 5.51 mmol), THF (20 mL), n-BuLi (2.5 M inhexanes, 4.5 mL, 11.3 mmol) and Br(CH2)5CH��CH2 (1.73 mL,11.4 mmol) were combined in a procedure analogous to thatfor 4a. An identical workup gave 4d (1.55 g, 5.12 mmol, 93%) asa colorless oil. Calc. for C20H31P: C, 79.47; H, 10.26. Found C,78.89; H, 10.61%.

NMR: 27 1H 7.54–7.53 (m, 2 H of Ph), 7.38–7.36 (m, 3 H ofPh), 5.82–5.80 (m, 2 H, 2CH��), 5.02–4.94 (m, 4 H, 2 ��CH2),2.05–2.00 (m, 4 H, 2CH2), 1.73–1.70 (m, 4 H, 2CH2), 1.45–1.36(m, 12 H, 6CH2);

13C{1H} 28 139.4 (d, 1JCP = 18.3, i-Ph), 139.3(s, CH��), 132.7 (d, 2JCP = 18.4, o-Ph), 129.0 (s, p-Ph), 128.6 (d,3JCP = 6.7, m-Ph), 114.7 (s, ��CH2), 34.0 (s, CH2), 31.1 (d, JCP =11.5, CH2), 29.0 (s, CH2), 28.6 (d, JCP = 11.0, CH2), 26.2 (d, JCP

= 13.6, CH2); 31P{1H} �23.3 (s).

MS: 29 303 (4d�, 100%), 206 ([4d � (CH2)5CH��CH2]�, 62%).

PPh((CH2)8CH��CH2)2 (4f)

PPhH2 (0.152 g, 1.38 mmol), THF (10 mL), n-BuLi (2.5 M inhexanes, 1.1 mL, 2.8 mmol) and Br(CH2)8CH��CH2 (0.55 mL,2.75 mmol) 3d were combined in a procedure analogous to thatfor 4a. An identical workup gave 4f (0.521 g, 1.35 mmol, 98%)as a colorless oil.30

NMR: 27 1H 7.52 (m, 2 H of Ph), 7.36 (m, 3 H of Ph), 5.80 (m,2 H, 2CH��), 5.03–4.92 (m, 4 H, 2 ��CH2), 2.08–2.00 (m, 4 H,2CH2), 1.37–1.27 (m, 28 H, 14CH2);

13C{1H} 28 139.6 (s, CH��),139.5 (d, 1JCP = 19.9, i-Ph), 132.7 (d, 2JCP = 18.3, o-Ph), 128.9 (s,p-Ph), 128.6 (d, 3JCP = 9.1, m-Ph), 114.5 (s, ��CH2), 34.2 (s, CH2),31.6 (d, JCP = 11.5, CH2), 29.7 (s, CH2), 29.6 (s, CH2), 29.5 (s,

CH2), 29.3 (s, CH2), 28.7 (d, JCP = 10.9, CH2), 26.3 (d, JCP =13.4, CH2);

31P{1H} �23.2 (s).MS: 29 387 (4f�, 100%).

trans-(Cl)(C6F5)Pt(PPh((CH2)2CH��CH2)2)2 (11a)

A Schlenk flask was charged with [Pt(µ-Cl)(C6F5)(S(CH2-CH2)2)]2 (12; 0.460 g, 0.474 mmol),9 4a (0.424 g, 1.945 mmol)and CH2Cl2 (30 mL). The pale green mixture was stirred (14 h)and became colorless. Solvent was removed by oil-pumpvacuum. The residue was filtered through neutral alumina(3.0 × 2.5 cm column) using 1 : 1 v/v CH2Cl2–hexanes. Solventwas removed from the product fraction by oil-pump vacuum toyield 11a as a colorless oil (0.627 g, 0.752 mmol, 79%). Calc. forC34H38ClF5P2Pt: C, 48.95; H, 4.56. Found: C, 49.33; H, 4.80%.

NMR: 27 1H 7.44 (m, 4 H of 2Ph), 7.35 (m, 6 H of 2Ph), 5.84–5.75 (m, 4 H, 4CH��), 5.03–4.97 (m, 8 H, 4 ��CH2), 2.37–2.27 (m,8 H, 4CH2), 2.19–2.09 (m, 8 H, 4CH2);

13C{1H} 31a,32,33 137.8(virtual t,34 JCP = 7.5, CH��), 131.6 (virtual t,34 JCP = 5.3, o-Ph),130.6 (s, p-Ph), 130.0 (virtual t,34 JCP = 26.0, i-Ph), 128.7 (virtualt,34 JCP = 4.8, m-Ph), 115.6 (s, ��CH2), 28.4 (s, PCH2CH2), 22.6(virtual t,34 JCP = 16.4, PCH2);

31P{1H} 10.7 (s, JPPt = 2564).35

IR (cm�1, oil film) 3080 (w), 2980 (w), 2934 (w), 2864 (w),1640 (m), 1502 (s), 1459 (s), 1436 (s), 1108 (m), 1058 (m), 953(s), 911 (s), 803 (s), 722 (s), 687 (s). MS: 29 798 ([11a � Cl]�,100%), 579 ([11a � Cl � 4a]�, 40%), 411 ([11a � Cl � C6F5 �4a]�, 80%), 219 (4a�, 80%), 164 ([4a � (CH2)4CH��CH2]

�, 70%).

trans-(Cl)(C6F5)Pt(PPh((CH2)3CH��CH2)2)2 (11b)

Complex 12 (0.430 g, 0.443 mmol), 4b (0.440 g, 1.79 mmol) andCH2Cl2 (25 mL) were combined in a procedure analogous tothat for 11a (17 h stirring). An identical workup gave 11b as acolorless oil (0.675 g, 0.759 mmol, 86%). Calc. for C38H46-ClF5P2Pt: C, 51.27; H, 5.17. Found: C, 50.48; H, 5.12%.

NMR: 27 1H 7.47–7.43 (m, 4 H of 2Ph), 7.35–7.30 (m, 6 H of2Ph), 5.76–5.66 (m, 4 H, 4CH��), 5.02–4.98 (m, 8 H, 4 ��CH2),2.19–2.07 (m, 12 H, 6CH2), 2.00–1.96 (m, 4 H, 2CH2), 1.81–1.70 (m, 4 H, 2CH2), 1.50–1.42 (m, 4 H, 2CH2);

13C{1H} 31,32,33

137.6 (s, CH��), 131.5 (virtual t,34 JCP = 5.3, o-Ph), 130.2 (s,p-Ph), 128.4 (virtual t,34 JCP = 4.8, m-Ph), 115.8 (s, ��CH2), 35.1(virtual t,34 JCP = 7.1, PCH2CH2CH2), 23.3 (s, PCH2CH2),22.5 (virtual t,34 JCP = 16.8, PCH2);

31P{1H} 10.2 (s, JPPt =2551).35

IR (cm�1, oil film) 3080 (w), 2980 (w), 2934 (w), 2864 (w),1640 (m), 1502 (s), 1459 (s), 1436 (s), 1108 (m), 1058 (m), 953(s), 911 (s), 803 (s), 722 (s), 687 (s). MS: 29 854 ([11b � Cl]�,80%), 606 ([11b � Cl � 4b]�, 40%), 440 ([11b � Cl � C6F5 �4b]�, 100%), 245 (4b�, 80%), 178 ([4b � (CH2)3CH��CH2]

�,100%).

trans-(Cl)(C6F5)Pt(PPh((CH2)4CH��CH2)2)2 (11c)

Complex 12 (0.522 g, 0.537 mmol), 4c (0.495 g, 1.81 mmol) andCH2Cl2 (30 mL) were combined in a procedure analogous tothat for 11a (18 h stirring). An identical workup gave 11c as acolorless oil (0.738 g, 0.780 mmol, 73%). Calc. for C42H54-ClF5P2Pt: C, 53.31; H, 5.71. Found: C, 53.45; H, 5.85%.

NMR: 27 1H 7.39 (m, 4 H of 2Ph), 7.29 (m, 6 H of 2Ph),5.71–5.60 (m, 4 H, 4CH��), 4.94–4.84 (m, 8 H, 4 ��CH2), 2.20–2.10 (m, 4 H, 2CH2), 2.03–1.96 (m, 12 H, 6CH2), 1.62–1.51 (m,4 H, 2CH2), 1.44–1.32 (m, 12 H, 6CH2);

13C{1H} 31a,32,33 138.6 (s,CH��), 131.6 (virtual t,34 JCP = 5.1, o-Ph), 130.6 (virtual t,34 JCP =25.9, i-Ph), 130.3 (s, p-Ph), 128.5 (virtual t,34 JCP = 4.7, m-Ph),115.2 (s, ��CH2), 33.6 (s, CH2), 30.7 (virtual t,34 JCP = 6.9,PCH2CH2CH2), 23.6 (s, CH2), 22.9 (virtual t,34 JCP = 16.6,PCH2);

31P{1H} 10.1 (s, JPPt = 2543).35

IR (cm�1, oil film) 3080 (w), 2930 (m), 2860 (w), 1640 (w),1502 (s), 1459 (s), 1440 (s), 1108 (m), 1061 (s), 957 (s), 911 (s),799 (s), 741 (s), 695 (s). MS: 29 910 ([11c � Cl]�, 40%), 741 ([11c� Cl � C6F5]

�, 20%), 467 ([11c � Cl � C6F5 � 4c]�, 50%), 385

1023D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

([11c � Cl � C6F5 � 4c � (CH2)4CH��CH2]�, 45%), 275 (4c�,

70%), 192 ([4c � (CH2)4CH��CH2]�, 100%).

trans-(Cl)(C6F5)Pt(PPh((CH2)5CH��CH2)2)2 (11d)

Complex 12 (0.260 g, 0.268 mmol), 4d (0.340 g, 1.13 mmol) andCH2Cl2 (20 mL) were combined in a procedure analogous tothat for 11a. An identical workup gave 11d as a colorless oil(0.497 g, 0.496 mmol, 93%). Calc. for C46H62ClF5P2Pt: C, 55.12;H, 6.19. Found: C, 54.75; H, 6.50.

NMR: 27 1H 7.43–7.41 (m, 4 H of 2Ph), 7.34–7.28 (m, 6 H of2Ph), 5.82–5.75 (m, 4 H, 4CH��), 5.01–4.93 (m, 8 H, 4 ��CH2),2.20–2.12 (m, 4 H, 2CH2), 2.01–1.95 (m, 12 H, 6CH2),1.70–1.55 (m, 4 H, 2CH2), 1.45–1.30 (m, 20 H, 10CH2);13C{1H} 31a,32,33 139.1 (s, CH��), 131.6 (virtual t,34 JCP = 5.1,o-Ph), 130.7 (virtual t,34 JCP = 26.1, i-Ph), 130.3 (s, p-Ph), 128.5(virtual t,34 JCP = 4.6, m-Ph), 114.9 (s, ��CH2), 33.9 (s, CH2), 31.0(virtual t,34 JCP = 7.0, PCH2CH2CH2), 28.7 (s, CH2), 24.1 (s,CH2), 23.1 (virtual t,34 JCP = 16.7, PCH2);

31P{1H} 10.2 (s, JPPt =2543).35

IR (cm�1, oil film) 3080 (w), 2930 (m), 2856 (m), 1640 (m),1502 (s), 1459 (s), 1440 (s), 1061 (s), 957 (s), 907 (s), 799 (s),741 (s), 694 (s). MS: 29 966 ([11d � Cl]�, 20%), 797 ([11d � Cl� C6F5]

�, 20%), 495 ([11d � Cl � C6F5 � 4d]�, 60%), 397 ([11d� Cl � C6F5 � 4d � (CH2)5CH��CH2]

�, 50%), 303 (4d�, 100%),192 ([4d � (CH2)5CH��CH2]

�, 70%).

trans-(Cl)(C6F5)Pt(PPh((CH2)6CH��CH2)2)2 (11e)

Complex 12 (0.416 g, 0.430 mmol), 4e (0.568 g, 1.719 mmol) 3c

and CH2Cl2 (30 mL) were combined in a procedure analogousto that for 11a (16 h stirring). A similar workup (2.5 × 2.5 cmcolumn, 3 : 1 v/v CH2Cl2–hexanes) gave 11e as a colorless oil(0.824 g, 0.779 mmol, 91%). Calc. for C50H70ClF5P2Pt: C, 56.73;H, 6.66. Found: C, 56.12; H, 6.58%.

NMR: 27 1H 7.40–7.37 (m, 4 H of 2Ph), 7.30–7.26 (m, 6 H of2Ph), 5.81–5.68 (m, 4 H, 4CH��), 4.98–4.89 (m, 8 H, 4��CH2),2.10–2.09 (m, 4 H, 4PCHH�), 2.01–1.89 (m, 12 H, 4PCHH�,4CH2CH��), 1.60–1.56 (m, 4 H, 4PCH2CHH�), 1.34–1.24(m, 28 H, 4PCH2CHH�, 12CH2);

13C{1H} 31a,32,33 138.9 (s, CH��),131.2 (virtual t,34 JCP = 5.1, o-Ph), 130.4 (virtual t,34 JCP = 25.8,i-Ph), 129.9 (s, p-Ph), 128.0 (virtual t,34 JCP = 4.4, m-Ph),114.3 (=CH2), 33.7 (s, CH2CH��), 31.0 (virtual t,34 JCP =6.5, PCH2CH2CH2), 28.7 (s, CH2), 28.6 (s, CH2), 23.7 (s, CH2),22.7 (virtual t,34 JCP = 16.5, PCH2);

31P{1H} 9.3 (s, 1JPPt =2540).35

IR (cm�1, powder film) 3080 (w), 2930 (m), 2856 (w), 1502 (s),1463 (s), 1436 (s), 1104 (m), 1061 (m), 1000 (m), 953 (s), 911 (s),803 (m), 741 (s), 690 (s). MS: 29 1059 (11e�, 2%), 1022([11e � Cl]�, 40%), 853 ([11e � Cl � C6F5]

�, 22%), 489 ([11e �Cl � C6F5 � 4e]�, 70%), 331 (4e�, 100%).

trans-(Cl)(C6F5)Pt(PPh((CH2)8CH��CH2)2)2 (11f)

Complex 12 (0.504 g, 0.519 mmol), 4f (0.839 g, 2.17 mmol) andCH2Cl2 (30 mL) were combined in a procedure analogous tothat for 11a (15 h stirring). An identical workup gave 11f as acolorless oil (0.898 g, 0.768 mmol, 74%). Calc. for C58H86-ClF5P2Pt: C, 59.80; H, 7.72. Found: C, 59.52; H, 7.35%.

NMR: 27 1H 7.43 (m, 4 H of 2Ph), 7.29 (m, 6 H of 2Ph), 5.82(m, 4 H, 4CH��), 4.98 (m, 8 H, 4 ��CH2), 2.14–1.94 (m, 16 H,8CH2), 1.58 (m, 4 H, 2CH2), 1.37–1.25 (m, 44 H, 22CH2);13C{1H} 31a,32,33 139.4 (s, CH��), 131.4 (virtual t,34 JCP = 5.1,o-Ph), 130.7 (virtual t,34 JCP = 25.6, i-Ph), 130.0 (s, p-Ph), 128.2(virtual t,34 JCP = 4.7, m-Ph), 114.3 (s, ��CH2), 34.0 (s, CH2), 31.4(virtual t,34 JCP = 6.9, PCH2CH2CH2), 29.7 (s, CH2), 29.3 (s,CH2), 29.3 (s, CH2), 29.0 (s, CH2), 24.0 (s, CH2), 22.9 (virtual t,34

JCP = 16.5, PCH2); 31P{1H} 10.1 (s, JPPt = 2540).35

IR (cm�1, oil film) 3080 (w), 2926 (s), 2856 (s), 1640 (w), 1502(s), 1459 (s), 1061 (m), 957 (s), 907 (s), 799 (m), 741 (s), 695 (s).MS: 29 1134 ([11f � Cl]�, 100%), 965 ([11f � Cl � C6F5]

�, 70%).

Metathesis of 11a; (Z,Z )-trans-(Cl)(C6F5)Pt-

(PPh(CH2)2CH��CH(CH2)2)2 ((Z,Z )-14a)

A two-necked flask was charged with 11a (0.465 g, 0.558mmol), Grubbs’ catalyst 2 (ca. half of 0.036 g, 0.0390 mmol, 14mol%) and CH2Cl2 (60 mL; the resulting solution is 0.0093 M in11a), and fitted with a condenser. The solution was refluxed.After 2 h, the remaining 2 was added. After 2 h, solvent wasremoved by oil-pump vacuum. The residue was filtered throughneutral alumina (2.5 × 2.5 cm column) using CH2Cl2. Solventwas removed from the filtrate by oil-pump vacuum to give(Z,Z )-14a as a pale pink solid (0.371 g, 0.477 mmol, 86%), mp218–220 �C (decomp.) (capillary). Calc. for C30H30ClF5P2Pt: C,46.31; H, 3.86. Found: C, 46.81; H, 4.28%.

NMR: 27 1H 7.45–7.39 (m, 4 H of 2Ph), 7.35–7.28 (m, 6 H of2Ph), 5.79–5.75 (m, 4 H, 2CH��CH), 2.55–2.43 (m, 8 H, 4CH2),2.32–2.20 (m, 8 H, 4CH2);

13C{1H} 31a,32 131.8 (s, CH��CH),131.3 (virtual t,34 JCP = 4.8, o-Ph), 130.4 (virtual t,34 JCP = 25.9,i-Ph), 130.3 (s, p-Ph), 128.8 (virtual t,34 JCP = 4.8, m-Ph), 22.4 (s,CH2), 21.5 (virtual t,34 JCP = 16.1, CH2);

31P{1H} 15.8 (s, JPPt =2511).35

IR (cm�1, powder film) 3030 (w), 2930 (w), 2856 (w), 1502 (s),1459 (s), 1058 (m), 953 (s), 718 (s), 695 (s). MS: 29 742 ([14a �Cl]�, 100%), 552 ([14a � Cl � PhP((CH2)CH��CH(CH2))]

�,30%).

trans-(Cl)(C6F5)Pt(PPh((CH2)6)2 (16a)

A two-necked flask was charged with 14a (0.371 g, 0.477mmol), 10% Pd/C (0.064 g, 0.0601 mmol Pd), ClCH2CH2Cl (20mL) and ethanol (20 mL), flushed with H2, and fitted with aballoon of H2. The mixture was stirred for 69 h. Solvent wasremoved by oil-pump vacuum. The residue was filtered throughneutral alumina (2.5 × 2.5 cm column) using 3 : 1 v/v hexanes–CH2Cl2. Solvent was removed from the filtrate by oil-pumpvacuum to give 16a as a white powder (0.240 g, 0.307 mmol,64%), mp 145 �C (capillary), 147 �C (DSC; T i/T e/T p/T c/T f

120.7/145.3/147.0/149.0/179.8 �C). TGA: onset of mass loss,285 �C (T e). Calc. for C30H34ClF5P2Pt: C, 46.07; H, 4.35.Found: C, 45.98; H, 4.43%.

NMR: 27 1H 7.44 (m, 4 H of 2Ph), 7.28 (m, 6 H of 2Ph),2.52–2.58 (m, 4 H, 2CH2), 2.28–2.24 (m, 4 H, 2CH2), 1.91–1.88(m, 4 H, 2CH2), 1.70–1.65 (m, 8 H, 4CH2), 1.55–1.53 (m, 4 H,2CH2);

13C{1H} 31a,32 132.1 (virtual t,34 JCP = 25.4, i-Ph), 131.2(virtual t,34 JCP = 4.8, o-Ph), 130.0 (s, p-Ph), 128.5 (virtual t,34

JCP = 4.7, m-Ph), 29.3 (s, CH2), 24.9 (virtual t,34 JCP = 15.9,CH2), 23.4 (s, CH2);

31P{1H} 11.2 (s, JPPt = 2488).35

IR (cm�1, powder film) 2926 (m), 2860 (w), 1502 (s), 1459 (s),1058 (s), 953 (s), 803 (s), 730 (s), 691 (s). MS: 29 782 (16a�, 40%),746 ([16a � Cl]�, 50%), 577 ([16a � Cl � C6F5]

�, 100%).

Metathesis of 11b

Complex 11b (0.176 g, 0.198 mmol), 2 (0.039 g, 0.0474 mmol,24 mol%), and CH2Cl2 (60 mL; resulting solution 0.0033 M in11b) were combined in a procedure analogous to that with 11a(1.5 h, second catalyst charge, then 1.5 h). A similar workup(2.5 × 3 cm column) gave a white powder comprised of poly-meric and/or oligomeric products (0.140 g, 0.168 mmol, 85%).

NMR: 27 1H 7.32 (m, 10 H, 2Ph), 5.30 (m, 4 H, 2CH��CH),2.02–1.25 (m, 24 H, 12CH2);

31P{1H} 10.0 (br s, JPPt = 2561).35

MS: 29 1632 ([2�Pt � Cl]�, 30%),36 1463 ([2�Pt � Cl � C6F5]�,

20%),36 630 (Pt(PPh((CH2)3CH��)2)2�, 100%).

Metathesis of 11c; syn-(E,E )-trans-(Cl)(C6F5)-

Pt(PPh(CH2)4CH��CH(CH2)4P(CH2)4CH��CH(CH2)4Ph)

(syn-(E,E )-13c)

Complex 11c (0.191 g, 0.202 mmol), 2 (0.020 g, 0.0242 mmol,12 mol%), and CH2Cl2 (300 mL; resulting solution is 0.00067 M

1024 D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

in 11c) were combined in a procedure analogous to that with11a (3 h, second catalyst charge, then 3 h; 31P{1H} NMR ofresidue (δ, CDCl3): 18.7 (28%), 12.6 (11%), 12.0 (19%), 11.6(23%), 11.1 (19%)) A similar workup (2.5 × 5 cm column using2 : 1 v/v hexanes–CH2Cl2; solvent removal from first fractions)gave syn-(E,E )-13c as a white solid (0.0379 g, 0.0426 mmol,21%), mp 265–268 �C (decomp.) (capillary). Calc. forC38H46ClF5P2Pt: C, 51.26; H, 5.17. Found: C, 51.12; H, 5.25%.

NMR: 27 1H 7.21 (m, 2 H of 2Ph), 7.13–7.10 (m, 8 H of 2Ph),5.50 (t, JHH = 3.6, 4 H, 2CH��CH), 2.53–2.45 (m, 8 H, 4CH2),2.29–2.25 (m, 4 H, 2CH2), 2.09–2.07 (m, 4 H, 2CH2), 1.97–1.93(m, 4 H, 2CH2), 1.82–1.79 (m, 4 H, 2CH2), 1.67–1.55 (m, 8 H,4CH2);

13C{1H} 31,32 131.5 (s, CH��CH), 130.7 (virtual t,34 JCP =4.7, o-Ph), 130.0 (s, p-Ph), 128.0 (virtual t,34 JCP = 4.6, m-Ph),32.2 (s, CH2), 31.1 (virtual t,34 JCP = 8.3, CH2), 27.4 (virtual t,34

JCP = 17.2, CH2), 25.8 (s, CH2); 31P{1H} 18.7 (s, JPPt = 2623).35

IR (cm�1, powder film) 2930 (m), 2849 (w), 1498 (s), 1455 (s),1436 (s), 1058 (s), 953 (s), 768 (s), 718 (s). MS: 29 890 (13c�,10%), 854 ([13c � Cl]�, 100%), 686 ([13c � Cl � C6F5]

�, 60%).The column was subsequently rinsed with CH2Cl2. Similar

concentration of the fractions gave a white solid (0.0754 g,0.0848 mmol, 42%) comprised of polymeric and/or oligomericproducts.

31P{1H} 12.6 (s, JPPt = 2583,35 19%), 12.0 (s, JPPt = 2552,35

14%), 11.6 (s, JPPt = 2573,35 45%), 11.1 (s, JPPt = 2498,35 22%).MS: 29 1742 ([2�Pt � Cl]�, 10%),36 1576 ([2�Pt � Cl � C6F5]

�,5%),36 549 ([13c � Cl � C6F5 � (CH2)10]

�, 100%).

syn-trans-(Cl)(C6F5)Pt(PPh(CH2)10P(CH2)10Ph) (syn-15c)

Complex 13c (0.0379 g, 0.0426 mmol), 10% Pd/C (0.019 g,0.018 mmol Pd), ClCH2CH2Cl (10 mL), ethanol (10 mL), andH2 were combined in a procedure analogous to that for 16a.After 132 h, a similar workup (column rinsed with 2 : 1 v/v hex-anes–CH2Cl2) gave syn-15c as a white powder (0.036 g, 0.0405mmol, 95%), mp 256–258 �C (decomp.) (capillary), 255 �C(DSC; T i/T e/T p/T c/T f 210.1/242.2/254.6/260.6/271.4 �C).TGA: onset of mass loss, 328 �C (T e). Calc. for C38H50ClF5-P2Pt: C, 51.04; H, 5.60. Found: C, 51.00; H, 5.61%.

NMR: 27 1H 7.18 (m, 2 H of 2Ph), 7.11 (m, 8 H of 2Ph), 2.56–2.53 (m, 4 H, 2CH2), 2.42–2.35 (m, 4 H, 2CH2), 1.97–1.84 (m, 8H, 4CH2), 1.70–1.63 (m, 10 H, 5CH2), 1.57–1.50 (m, 10 H,5CH2), 1.48–1.40 (m, 4 H, 2CH2);

13C{1H} 31a,32 130.9 (virtualt,34 JCP = 24.1, i-Ph), 130.7 (virtual t,34 JCP = 5.2, o-Ph), 130.0 (s,p-Ph), 127.9 (virtual t,34 JCP = 4.6, m-Ph), 29.5 (virtual t,34 JCP =7.3, CH2), 27.4 (s, CH2), 26.6 (virtual t,34 JCP = 17.1, CH2), 25.7(s, CH2), 24.8 (s, CH2);

31P{1H} 16.2 (s, JPPt = 2612).35

IR (cm�1, oil film) 2926 (w), 2856 (w), 1502 (m), 1459 (m),1231 (s), 1119 (s), 980 (s), 953 (s), 803 (m), 741 (m), 695 (m).MS: 29 894 (15c�, 35%), 858 ([15c � Cl]�, 100%), 689 ([15c � Cl� C6F5]

�, 50%).

Metathesis of 11d; syn-trans-(Cl)(C6F5)Pt(PPh(CH2)12P(CH2)12-

Ph) (syn-15d)

Complex 11d (0.103 g, 0.103 mmol), 2 (0.018 g, 0.0218 mmol,21 mol%), and CH2Cl2 (55 mL; resulting solution 0.0019 M in11d) were combined in a procedure analogous to that with 11a(2 h, second catalyst charge, 2 h). The residue (31P{1H} NMR(δ, CDCl3): 10.6 (s, 12%), 10.1 (br s, JPPt = 2532.1, 88%)) 35 wascharged with 10% Pd/C (0.030 g, 0.028 mmol Pd), ClCH2CH2Cl(10 mL) and ethanol (10 mL), flushed with H2, and fitted with aballoon of H2. The mixture was stirred for 144 h. Solvent wasremoved by oil-pump vacuum. The residue was filtered throughneutral alumina (2.5 × 2.5 cm column) using 3 : 1 v/v hexanes–CH2Cl2. Solvent was removed from the filtrate to give syn-15das a white powder (0.005 g, 0.0053 mmol, 5%). Calc. forC42H58ClF5P2Pt: C, 53.08; H, 6.11. Found: C, 53.34; H, 6.12%.

NMR: 27 1H 7.21–7.12 (m, 10 H, 2Ph), 2.53 (m, 4 H, 2CH2),2.17 (m, 4 H, 2CH2), 1.95–1.80 (m, 8 H, 4CH2), 1.56–1.41 (m,

32 H, 16CH2); 13C{1H} 31,32 130.9 (virtual t,34 JCP = 4.5, o-Ph),

130.0 (s, p-Ph), 127.9 (virtual t,34 JCP = 3.7, m-Ph), 30.2 (virtualt,34 JCP = 7.4, CH2), 27.8 (s, CH2), 27.3 (s, CH2), 26.8 (virtual t,34

JCP = 17.2, CH2), 26.5 (s, CH2), 24.9 (s, CH2); 31P{1H} 12.5

(s, JPPt = 2590).35

MS: 29 949 (15d�, 30%), 913 ([15d � Cl]�, 100%), 743([15d � Cl � C6F5]

�, 70%).

Metathesis of 11e; trans-(Cl)(C6F5)-

Pt(PPh(CH2)6CH��CH(CH2)6P(CH2)6CH��CH(CH2)6Ph) (13e)

Complex 11e (0.250 g, 0.236 mmol), 2 (0.0019 g, 0.0231 mmol,10 mol%), and CH2Cl2 (70 mL; resulting solution 0.0034 M in11e) were combined in a procedure analogous to that with 11a(2.5 h, second catalyst charge, 2.5 h). An identical workup gave13e and other metathesis products as a pale pink powder (0.230g, 0.230 mmol, 97%). Calc. for C46H62ClP2F5Pt: C, 55.12; H,6.23. Found: C, 54.91; H, 6.00%.

NMR: 27 1H 7.41–7.05 (m, 10 H, 2Ph), 5.35–5.20 (m, 4 H,2CH��), 2.40–2.33 (m, 2 H of 4PCH2), 2.02–1.76 (m, 18 H; 6 Hof 4PCH2, 4 H of 4PCH2CH2, 4CH2CH��), 1.48–1.23 (m, 28 H;4 H of 4PCH2CH2, 12CH2);

31P{1H} (partial) 15.2 (s, 4%), 14.8(s, 5%), 13.5 (s, 1JPtP = 2579,35 44%), 12.3 (s, 9%), 10.9 (s, 8%),9.3 (s, 12%), 8.7 (s, 18%).

IR (cm�1, powder film) 3057 (w), 2926 (w), 2853 (m), 1502(m), 1459 (m), 1436 (m), 1104 (m), 1058 (m), 957 (s), 803 (m),737 (s), 690 (s). MS: 29 1969 ([2�Pt � Cl]�, 30%),36 1798([2�Pt � Cl � C6F5]

�, 20%),36 966 ([13e � Cl]�, 45%), 797 ([13e� Cl � C6F5]

�, 100%).

trans-(Cl)(C6F5)Pt(PPh(CH2)14P(CH2)14Ph) (15e)

Complex 13e and other metathesis products (0.154 g, 0.153mmol), 10% Pd/C (0.016 g, 0.015 mmol Pd), ClCH2CH2Cl (6.5mL), ethanol (6.5 mL), and H2 were combined in a procedureanalogous to that for 16a. After 48 h, a similar workup (3 ×2.5 cm column rinsed with CH2Cl2) gave crude 15e as a whitepowder (0.119 g, 0.118 mmol, 77%).

NMR: 27 1H 7.45–7.12 (m, 10 H, 2Ph), 2.40–2.36 (m, 4 H,2PCH2), 2.15–2.14 (m, 4 H, 2PCH2), 1.88–1.87 (m, 4 H,2PCH2CH2), 1.77–1.75 (m, 4H, 2PCH2CH2), 1.46–1.23 (m, 40H, 20CH2);

31P{1H} (partial) 11.8 (s, 1JPtP = 2579,35 15e, 52%).MS: 29 1977 ([2�Pt � Cl]�, 20%),36 1809 ([2�Pt � Cl � C6F5]

�,10%),36 1006 (15e�, 40%), 970 ([15e � Cl]�, 100%), 801 ([15e �Cl � C6F5]

�, 90%).The sample was chromatographed on neutral alumina (10 ×

2.5 cm column) using 1 : 3 v/v CH2Cl2–hexanes. The two leastpolar fractions were collected to give syn-15e (0.048 g, 0.0477mmol, 31%) as a white powder, mp 155–157 �C, and anti-15e(0.011g, 0.0100 mmol, 7%) as a white powder.

syn-15e: Calc. for C46H66ClP2F5Pt: C, 54.89; H, 6.61. Found:C, 54.93; H, 6.75.

NMR: 27 1H 33b 7.17–7.08 (m, 10 H, 2Ph), 2.35–2.28 (m, 4 H,4PCHH�), 2.15–2.04 (m, 4 H, 4PCHH�), 1.82–1.80 (m, 4 H,4PCH2CHH�), 1.73 (m, 4 H, 4PCH2CHH�), 1.47–1.11 (m, 40H, 20CH2);

13C{1H} 31a,32,33 130.3 (virtual t,34 JCP = 4.6, o-Ph),130.2 (virtual t,34 JCP = 26.0, i-Ph), 129.5 (s, p-Ph), 127.6 (virtualt,34 JCP = 4.4, m-Ph), 30.4 (virtual t,34 JCP = 6.4, PCH2CH2CH2),27.9 (s, CH2), 27.3 (s, CH2), 27.0 (s, CH2), 26.9 (s, CH2), 24.2 (sand overlapping virtual t,34 JCP = 17.5, PCH2CH2 and PCH2);31P{1H} 11.8 (s, 1JPtP = 2560).35

IR (cm�1, powder film) 2926 (m), 2856 (m), 1502 (s), 1463(m), 1058 (m), 957 (s). MS: 29 1006 (15e�, 40%), 970 ([15e �Cl]�, 100%), 801 ([15e � Cl � C6F5]

�, 60%).anti-15e: Calc. for C46H66ClP2F5Pt: C, 54.89; H, 6.61. Found:

C, 54.87; H, 6.91.NMR: 27 1H 7.82–7.78 (m, 2H of 2Ph), 7.41–7.39 (4H of 2Ph),

7.30–7.10 (m, 4H of 2Ph), 2.30–2.26 (m, 2 H of 4PCHH�),37

2.14–2.05 (m, 2 H of 4PCHH�),37 1.87–1.82 (m, 4 H of4PCHH�),37 1.62–1.10 (m, 48 H, 24CH2);

13C{1H} (partial,

1025D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

some assignments tentative) 31a,37 133.7 (s, m-Ph), 133.6 (s,m-Ph�), 130.4 (br s, 2 p-Ph), 129.60 (s, i-Ph), 129.58 (s, i-Ph�),127.8 (virtual t,34 JCP = 8.5, o-Ph), 127.99 (virtual t,34 JCP = 8.5,o-Pp�), 30.06 (virtual t,34 JCP = 11.5, CH2), 30.04 (virtual t,34 JCP

= 11.5, CH2), 28.2 (s, CH2), 28.0 (s, CH2), 27.7 (br s, CH2), 27.4(br s, CH2), 27.1 (br s, CH2), 26.9 (br s, CH2), 24.2 (br s, CH2),23.7 (br s, CH2);

31P{1H} 15.8 (2JPP� = 426.8, 1JPPt = 2610),35 11.2(2JP�P = 426.8, 1JP�Pt = 2556).35

IR (cm�1, powder film) 2926 (s), 2856 (s), 2362 (w), 2335 (w),1502 (s), 1459 (m), 1440 (s), 1061 (s), 957 (s). MS: 29 1006 (15e�,20%), 971 ([15e � Cl]�, 90%), 799 ([15e � Cl � C6F5]

�, 100%).

Metathesis of 11f: trans-(Cl)(C6F5)-

Pt(PPh(CH2)8CH��CH(CH2)8P(CH2)8CH��CH(CH2)8Ph) (13f)

Complex 11f (0.273 g, 0.233 mmol), 2 (ca. half of 0.050 g,0.0608 mmol, 26 mol%), and CH2Cl2 (70 mL; resulting solution0.0033 M in 11f ) were combined in a procedure analogous tothat with 11a (2 h, second catalyst charge, 3.5 h). A similarworkup (2.5 × 3 cm column) gave 13f and other metathesisproducts as a pale pink solid (0.238 g, 0.214 mmol, 92%). Calc.for C54H78ClF5P2Pt: C, 58.20; H, 6.88. Found: C, 57.84; H,7.30%.

NMR: 27 1H 7.44–7.14 (m, 10 H, 2Ph), 5.36 (m, 4 H, 2CH��CH), 2.27–1.86 (m, 16 H, 8CH2), 1.46–1.11 (m, 48 H, 24CH2);31P{1H} 13.5 (s, 7%), 13.1 (s, JPPt = 2566,35 34%), 12.6 (11%),10.7 (s, JPPt = 2522,35 23%), 10.5 (s, JPPt = 2522, 25%).35

MS: 29 1079 ([13f � Cl]�, 100%), 909 ([13f � Cl � C6F5]�,

80%).

syn-trans-(Cl)(C6F5)Pt(PPh(CH2)18P(CH2)18Ph) (syn-15f)

Complex 13f and other metathesis products (0.171 g, 0.154mmol), 10% Pd/C (0.027 g, 0.0262 mmol Pd), ClCH2CH2Cl(10 mL), ethanol (10 mL), and H2 were combined in a pro-cedure analogous to that for 16a. After 71 h, a similar workup(31P{1H} NMR of residue (δ, CDCl3): 11.9 (8%), 10.8 (39%),10.3 (27%), 10.1 (21%), 8.7 (5%); 2.5 × 5 cm column) gavesyn-15f as a colorless oil (0.026 g, 0.023 mmol, 15%).30

NMR: 27 1H 7.50–7.10 (m, 10 H, 2Ph), 2.15 (m, 10 H, 5CH2),1.35 (m, 62 H, 31CH2);

13C{1H} 31a,32 131.4 (virtual t,34 JCP = 4.9,o-Ph), 130.8 (virtual t,34 JCP = 26.0, i-Ph), 130.1 (s, p-Ph), 128.3(virtual t,34 JCP = 4.8, m-Ph), 31.0 (virtual t,34 JCP = 6.8, CH2),28.9, 28.8, 28.7, 28.6, 28.5, 28.4, 24.1 (s, CH2), 23.6 (virtual t,34

JCP = 17.2, CH2); 31P{1H} 10.8 (s, JPPt = 2551).35

MS: 29 1081 ([15f � Cl]�, 100%), 913 ([15f � Cl � C6F5]�,

90%).

H3B�PPh((CH2)6CH��CH2)2 (17e)

A Schlenk flask was charged with 4e (0.304g, 0.920 mmol) 3c

and THF (2 mL), cooled to �20 �C (N2, acetone), and H3B�SMe2 (0.0698g, 0.920 mmol) was added. The solution wasstirred for 1 h at �20 �C and 30 min at room temperature.Solvent was removed by rotary evaporation and oil-pumpvacuum. The residue was filtered through neutral alumina (6 ×2.5 cm column) using 1 : 1 v/v CH2Cl2–hexanes. Solvent wasremoved from the product fraction by oil-pump vacuum to give17e as a colorless oil (0.205 g, 0.595 mmol, 65%). Calc. forC22H38BP: C, 76.74; H, 11.12. Found: C, 76.46; H, 11.39%.

NMR: 27 1H 7.73–7.70 (m, 2 H of Ph), 7.60–7.47 (m, 3 H ofPh), 5.82–5.76 (m, 2 H, 2CH��), 5.01–4.92 (m, 4 H, 2 ��CH2),2.02–1.99 (m, 4 H, 2CH2CH��), 1.87–1.81 (m, 4 H, 2PCH2), 1.57(m, 2 H, CH2), 1.37–1.26 (m, 14 H, 7CH2), 1.0–0.2 (br, 3 H,BH3);

13C{1H} 28 138.6 (s, CH��), 131.8 (d, JCP = 7.6, o-Ph), 131.1(d, JCP = 2.2, p-Ph) 128.7 (d, JCP = 9.5, m-Ph), 128.6 (d, 1JCP =51.3, i-Ph), 114.5 (s, ��CH2), 33.6 (s, CH2CH��), 30.9 (d, JCP =13.0, CH2), 28.6 (s, CH2), 28.5 (s, CH2), 25.6 (d, JCP = 36.0,CH2), 22.7 (s, CH2);

31P{1H} 15.3 (apparent d, 1J(11B,31P) =75.1).

IR (cm�1, oil film) 2930, 2856, 2374, 2339, 1640, 1463, 1436,1116, 1061, 996, 907, 799, 745, 695. MS: 29 341 ([17e � 3H]�,38

40%), 331 ([17e � H3B]�, 100%).

H3B�PPh(CH2)6CH��CH(CH2)6 (18e)

A two-necked flask was charged with 17e (0.141 g, 0.409 mmol),2 (ca. half of 0.017 g, 0.0205 mmol, 5 mol%), and CH2Cl2 (180mL, the resulting solution is 0.0023 M in 17e), and fitted witha condenser. The solution was refluxed. After 2.5 h, theremaining 2 was added. After 2.5 h, solvent was removed byrotary evaporation and oil-pump vacuum. The residue wasfiltered through neutral alumina (5 × 2.5 cm column) usingCH2Cl2. Solvent was removed from the filtrate by rotary evap-oration and oil-pump vacuum to give 18e as a pale pink oil(0.080 g, 0.253 mmol, 62%). Calc. for C20H34BP: C, 75.95; H,10.83. Found: C, 75.20; H, 11.25%.

NMR: 27 1H 7.72–7.70 (m, 2 H of Ph), 7.49–7.46 (m, 3 H ofPh), 5.47–5.43/5.42–5.39/5.38–5.33 (3m, 2 H, 2CH��), 2.13–1.82(m, 8 H, 2CH2CH��, 2PCH2), 1.57–1.27 (m, 16 H, 8CH2),1.0–0.3 (br, 3H, BH3);

31P{1H} 15.2 (m).IR (cm�1, oil film) 2926, 2853, 2370, 2339, 1436, 1112, 1061,

969, 741, 695. MS: 29 629 ([2�P]�, 20%),36 617 ([2�P � H3B]�,25%),36 605 ([2�P � 2H3B]�, 30%),36 315 (18e�, 80%), 303 ([18e� H3B]�, 100%).

H3B�PPh(CH2)14 (19e)

A Fischer–Porter bottle was charged with 18e (0.072 g, 0.228mmol), Rh(PPh3)3(Cl) (0.021 g, 0.0028 mmol, 10 mol%), andbenzene (25 mL), and flushed with H2. The mixture was stirredunder H2 (6 atm) for 20 h. Solvent was removed by oil-pumpvacuum. The residue was chromatographed on neutral alumina(10 × 2.5 cm column) using 1 : 1 v/v CH2Cl2–hexanes. Solventwas removed from the product fraction by oil-pump vacuum togive 19e as a colorless oil (0.056 g, 0.176 mmol, 77%). Calc. forC20H36BP: C, 75.74; H, 11.40. Found: C, 75.28; H, 11.54%.

NMR: 27 1H 7.73–7.70 (m, 2 H of Ph), 7.49–7.46 (m, 3 H ofPh), 2.00–1.84 (m, 4 H, 2PCH2), 1.57–1.21 (m, 24 H, 12CH2),1.1–0.3 (br, 3H, BH3);

13C{1H} 28 131.3 (d, JCP = 8.2, o-Ph),130.9 (d, JCP = 2.3, p-Ph) 130.2 (d, 1JCP = 53.1, i-Ph), 128.7 (d,JCP = 9.5, m-Ph), 28.9 (d, JCP = 11.5, CH2), 26.8 (s, CH2), 26.57(s, CH2), 26.54 (s, CH2), 26.3 (s, CH2), 23.8 (d, JCP = 34.5, CH2),21.5 (d, JCP = 2.4, CH2);

31P{1H} 15.4 (apparent d, 1J(11B,31P) =69.6).

IR (cm�1, oil film) 2926, 2853, 2374, 2343, 1459, 1435, 1112,1065, 1000, 737, 691. MS: 29 609 ([2�P � 2H3B]�, 30%),36 315([19e � 3H]�, 100%),38 305 ([19e � H3B]�, 60%).

trans-(Cl)(C6F5)Pt(PPh(CH2)14)2 (16e)

A Schlenk flask was charged with 19e (0.112 g, 0.352 mmol)and HNEt2 (2 mL). The mixture was heated to 50 �C and stirredfor 45 min. The HNEt2 was removed by oil-pump vacuum, andthe residue vacuum dried at 50 �C for an additional 20 min.This operation was repeated twice (final cycle: 2 h, 50 �C) to

give crude PPh(CH2)14 (20e). The flask was charged with 12(0.085 g, 0.088 mmol) 9 and CH2Cl2 (6 mL), and the mixturewas stirred (16 h). Solvent was removed by oil-pump vacuum.The residue was chromatographed on neutral alumina (9 × 2.5cm column) using 1 : 1 v/v CH2Cl2–hexanes. Solvent wasremoved from the product fraction by oil-pump vacuum toyield 16e as a colorless oil, which solidified over the course ofseveral days (0.042 g, 0.0417 mmol, 24% based on 19e). Calc.for C46H66ClF5P2Pt: C, 54.89; H, 6.61. Found: C, 54.71; H,6.55%.

NMR: 27 1H 7.50–7.45 (m, 4 H of 2Ph), 7.36–7.28 (m, 6 H of2Ph), 2.16–2.12 (m, 4 H of 4PCHH�),37 1.95–1.92 (m, 4 H of4PCHH�),37 1.65–1.63 (m, 4 H of 4PCH2CHH�),37 1.56–1.30(m, 44 H; 4 H of 4PCH2CHH�, 20CH2);

37 13C{1H} 31a,32,33 131.2

1026 D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

(virtual t,34 JCP = 5.2, o-Ph), 130.9 (virtual t,34 JCP = 25.8, i-Ph),129.8 (s, p-Ph), 128.1 (virtual t,34 JCP = 4.7, m-Ph), 28.9 (virtualt,34 JCP = 6.6, PCH2CH2CH2), 26.8 (s, CH2), 26.63 (s, CH2),26.59 (s, CH2), 26.3 (s, CH2), 21.8 (s, CH2), 21.2 (virtual t,34 JCP

= 16.6, PCH2); 31P{1H} 7.2 (s, 1JPPt = 2520).35

IR (cm�1, powder film) 2926, 2856, 2374, 1502, 1455, 1112,1061, 957, 803, 745, 695. MS: 29 1006 (16e�, 15%), 970 ([16e �Cl]�, 40%), 801 ([16e � Cl � C6F5]

�, 60%)]�, 495 ([16e � Cl �C6F5 � 20e]�, 90%), 305 (20e�, 100%).

Crystallography.15

Toluene solutions of syn-15e, anti-15e and 16e were layeredwith ethanol. The samples were stored at �20 �C. After three tothirty days, colorless prisms had formed. Complexes 16a, syn-(E,E )-13c, and syn-15c were suspended in methanol andwarmed. THF was added until the samples were homogeneous.The mixtures were kept at room temperature. After one day,colorless prisms had formed.

Data were collected as outlined in Table 1. Cell parameterswere obtained from 10 frames using a 10� scan and refined with≥6873 reflections (syn-15e, 10003; anti-15e, 7885; 16e, 9914;16a, 6873; syn-(E,E )-13c, 8701; syn-15c, 23439). Lorentz,polarization, and absorption corrections were applied.39 Thespace groups were determined from systematic absences andsubsequent least-squares refinement. The structures weresolved by direct methods. The parameters were refined with alldata by full-matrix-least-squares on F 2 using SHELXL-97.40

Non-hydrogen atoms were refined with anisotropic thermalparameters. The hydrogen atoms were fixed in idealizedpositions using a riding model. Scattering factors were takenfrom literature.41 The quality of the crystal of syn-15c, whichcontained two independent molecules in the unit cell, was lowerthan the others.

CCDC reference numbers: syn-15e, 159809; anti-15e, 227266;16e, 227267; 16a, 227269; syn-(E,E )-13c, 227270; syn-15c,227268.

See http://www.rsc.org/suppdata/dt/b4/b400156g/ for crystal-lographic data in CIF or other electronic format.

Acknowledgements

We thank the Deutsche Forschungsgemeinschaft (DFG,GL 300/1–3), Alexander von Humboldt Foundation (Fellow-ship to T. S.), and Johnson Matthey PMC (platinum andruthenium loans) for support.

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8 M. A. Bennett, H. W. Kouwenhoven, J. Lewis and R. S. Nyholm,J. Chem. Soc., 1964, 4570.

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10 R. Usón, J. Forniés, P. Espinet, R. Navarro and C. Fortuño, J. Chem.Soc., Dalton Trans., 1987, 2077.

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13 M. Leconte, I. Jourdan, S. Pagano, F. Lefebvre and J.-M. Basset,J. Chem. Soc., Chem. Commun., 1995, 857.

14 T. Imamoto, T. Kusumoto, N. Suzuki and K. Sato, J. Am. Chem.Soc., 1985, 107, 5301.

15 The atom numbering in Tables 2 and 3, and Figs. 1–3, 5, and 6, hasbeen altered from those in the CIF files to facilitate comparisonsbetween molecules.

16 (a) J. C. Collings, K. P. Roscoe, E. G. Robins, A. S. Batsanov,L. M. Stimson, J. A. K. Howard, S. J. Clark and T. B. Marder,New J. Chem., 2002, 26, 1740, and references therein.; (b) F. Ponzini,R. Zagha, K. Hardcastle and J. S. Siegel, Angew. Chem., 2000, 112,2413; F. Ponzini, R. Zagha, K. Hardcastle and J. S. Siegel, Angew.Chem., Int. Ed., 2000, 39, 2323; (c) G. W. Coates, A. R. Dunn,L. M. Henling, J. W. Ziller, E. B. Lobkovsky and R. H. Grubbs,J. Am. Chem. Soc., 1998, 120, 3641; (d ) M. L. Renak,G. P. Bartholomew, S. Wang, P. J. Ricatto, R. J. Lachicotte and G. C.Bazan, J. Am. Chem. Soc., 1999, 121, 7787.

17 J. Sandström, Dynamic NMR Spectroscopy, Academic Press,New York, 1982; calculations utilized eqn. 7.4c.

18 (a) B. L. Shaw, J. Am. Chem. Soc., 1975, 97, 3856; (b) A. Pryde,B. L. Shaw and B. Weeks, J. Chem. Soc., Dalton. Trans., 1976, 322.

19 While this paper was being reviewed, we found that syn-(E,E )-13ccould be isolated in up to 58% yield using Grubbs’ “secondgeneration” catalyst Ru(��CHPh)(H2IMes)(PCy3)(Cl)2 (20 mol%)and extended reaction times that partially transform the byproducts.Analogous enhancements were not observed with 11d,f, nor with themetatheses in Scheme 1.3d These results will described, together withdata for other advanced-generation catalysts, at a later date.

20 P. L. Ng and J. N. Lambert, Synlett, 1999, 1749.21 (a) P. G. Sammes and D. J. Weller, Synthesis, 1995, 1205; (b) M. D. E.

Forbes, J. T. Patton, T. L. Myers, H. D. Maynard, D. W. Smith, Jr.,G. R. Schulz and K. B. Wagener, J. Am. Chem. Soc., 1992, 114,10978.

22 E. B. Bauer, S. Szafert, F. Hampel and J. A. Gladysz,Organometallics, 2003, 22, 2184.

23 E. B. Bauer, Doctoral Dissertation, Universität Erlangen-Nürnberg,2003.

24 A. Bondi, J. Phys. Chem., 1964, 68, 441.25 T. Shima, F. Hampel, J. A. Gladysz, manuscript in preparation.26 H. K. Cammenga and M. Epple, Angew. Chem., 1995, 107, 1284;

H. K. Cammenga and M. Epple, Angew. Chem., Int. Ed., 1995, 34,1171.

27 δ, CDCl3; all J values are in Hz.28 The PC6H5

13C NMR signals were assigned as described byB. E. Mann, J. Chem. Soc., Perkin Trans. 2, 1972, 30; that with thechemical shift closest to benzene was attributed to the meta carbon,and the least intense phosphorus-coupled signal was attributed tothe ipso, carbon.

1027D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8

29 FAB, 3-NBA, m/z, (relative intensity, %); the most intense peak ofisotope envelope is given.

30 A satisfactory microanalysis was not obtained.31 (a) The C6F5

13C NMR signals were not observed. These requirelarger numbers of transients due to the fluorine and platinumcouplings; (b) The ipso PC6H5

13C NMR signals were notobserved.

32 The PtPC6H5 13C NMR assignments have abundant precedent. See,

for example: P. W. Jolly and R. Mynott, Adv. Organomet. Chem.,1981, 19, 257.

33 (a) For syn-15e, the PtPCH2CH2CH2 13C assignments were

confirmed by a 1H,13C COSY spectrum. The corresponding signalsin 11b–f and 16e, and the PtPCH2CH2CH�� signals of 11a, wereassigned by analogy; (b) The 1H assignments for syn-15e were in turnverified by a 1H,1H COSY experiment.

34 P. S. Pregosin and L. M. Venanzi, Chem. Br., 1978, 276; the apparent,coupling between adjacent peaks of the triplet is given.

35 This coupling represents a satellite (d; 195Pt = 33.8%), and is notreflected in the peak multiplicity given.

36 The abbreviations 2�Pt and 2�P indicate ions with twice the mass ofthe expected monoplatinum or monophosphorus products.

37 The PCH2CH2 1H and C6H5

13C NMR signals were assigned byanalogy to syn-15e.

38 The isotope envelope calculated for this ion agreed with thatobserved. For phosphine boranes that give analogous ions, see ref.12a.

39 (a) “Collect” data collection software, Nonius B.V., Delft, 1998; (b)“Scalepack” data processing software Z. Otwinowski and W. Minor,Methods Enzymol. A, 1997, 276, 307.

40 G. M. Sheldrick, SHELX-97, Program for refinement of crystalstructures, University of Göttingen, 1997.

41 D. T. Cromer and J. T. Waber, in International Tables for X-rayCrystallography, ed. J. A. Ibers and W. C. Hamilton, Kynoch Press,Birmingham, England, 1974.

1028 D a l t o n T r a n s . , 2 0 0 4 , 1 0 1 2 – 1 0 2 8